diff --git a/include/playeritem.h b/include/playeritem.h
new file mode 100644
index 00000000..ae990a56
--- /dev/null
+++ b/include/playeritem.h
@@ -0,0 +1,32 @@
+#ifndef PLAYERITEM_H
+#define PLAYERITEM_H
+
+typedef enum {
+    PLAYER_ITEM_NONE,
+    PLAYER_ITEM_SWORD,
+    PLAYER_ITEM_BOMB,
+    PLAYER_ITEM_3,
+    PLAYER_ITEM_BOW,
+    PLAYER_ITEM_SHIELD,
+    PLAYER_ITEM_LANTERN,
+    PLAYER_ITEM_7,
+    PLAYER_ITEM_GUST_JAR,
+    PLAYER_ITEM_PACCI_CANE,
+    PLAYER_ITEM_A,
+    PLAYER_ITEM_B,
+    PLAYER_ITEM_C,
+    PLAYER_ITEM_CELL_OVERWRITE_SET,
+    PLAYER_ITEM_BOTTLE,
+    PLAYER_ITEM_SWORD_BEAM1,
+    PLAYER_ITEM_10,
+    PLAYER_ITEM_11,
+    PLAYER_ITEM_12,
+    PLAYER_ITEM_13,
+    PLAYER_ITEM_14,
+    PLAYER_ITEM_15,
+    PLAYER_ITEM_SWORD_BEAM2,
+    PLAYER_ITEM_17,
+    PLAYER_ITEM_CELL_OVERWRITE_SET2,
+} PlayerItem;
+
+#endif
\ No newline at end of file
diff --git a/src/code_08077B98.c b/src/code_08077B98.c
index 2d011e33..970644d3 100644
--- a/src/code_08077B98.c
+++ b/src/code_08077B98.c
@@ -83,7 +83,7 @@ void* sub_08077C54(UnkItemStruct* unk) {
 Entity* sub_08077C94(ItemBehavior* arg0, u32 arg1) {
     Entity* iVar1;
 
-    iVar1 = FindEntityByID(8, gUnk_0811BE48[arg1].unk0[3], 2);
+    iVar1 = FindEntityByID(PLAYER_ITEM, gUnk_0811BE48[arg1].unk0[3], 2);
     if (iVar1 == NULL) {
         return NULL;
     }
diff --git a/src/enemy/pesto.c b/src/enemy/pesto.c
index 9fa20418..f89f23e0 100644
--- a/src/enemy/pesto.c
+++ b/src/enemy/pesto.c
@@ -10,6 +10,7 @@
 #include "game.h"
 #include "functions.h"
 #include "save.h"
+#include "playeritem.h"
 
 void sub_080249F4(Entity*);
 void sub_08024940(Entity*);
@@ -659,7 +660,7 @@ bool32 sub_08024B38(Entity* this) {
         }
     }
 
-    ent = FindEntityByID(8, 2, 2);
+    ent = FindEntityByID(PLAYER_ITEM, PLAYER_ITEM_BOMB, 2);
     if (ent) {
         do {
             if (ent->action != 2 && ent->z.HALF.HI == 0 && sub_08049F1C(this, ent, 0xa0)) {
@@ -676,7 +677,7 @@ bool32 sub_08024B38(Entity* this) {
         return iVar4;
     }
 
-    ent = FindEntityByID(6, 5, 6);
+    ent = FindEntityByID(OBJECT, POT, 6);
     if (ent) {
         do {
             if (ent->action == 1 && sub_08049F1C(this, ent, 0xa0)) {
diff --git a/src/item/itemBomb.c b/src/item/itemBomb.c
index 4cba1598..4154e1f6 100644
--- a/src/item/itemBomb.c
+++ b/src/item/itemBomb.c
@@ -2,6 +2,7 @@
 #include "coord.h"
 #include "sound.h"
 #include "functions.h"
+#include "playeritem.h"
 
 extern void (*const gUnk_0811BD98[])(ItemBehavior*, u32);
 
@@ -23,7 +24,8 @@ void sub_08075FF8(ItemBehavior* this, u32 arg1) {
 
     if ((gPlayerState.jump_status | gPlayerState.field_0x3[1]) == 0) {
         bombCount = 0;
-        for (entity = FindEntityByID(8, 2, 2); entity != NULL; entity = FindNextDuplicateID(entity, 2)) {
+        for (entity = FindEntityByID(PLAYER_ITEM, PLAYER_ITEM_BOMB, 2); entity != NULL;
+             entity = FindNextDuplicateID(entity, 2)) {
             bombCount += 1;
         }
         maxBombs = this->behaviorID == 7 ? 3 : 1;
diff --git a/src/item/itemSword.c b/src/item/itemSword.c
index bcba4054..ae15069d 100644
--- a/src/item/itemSword.c
+++ b/src/item/itemSword.c
@@ -112,7 +112,7 @@ void sub_080754B8(ItemBehavior* this, u32 arg1) {
 
         if (gPlayerEntity.frameSpriteSettings & 1) {
             iVar1 = sub_0807B014();
-            if (iVar1 && FindEntityByID(PLAYER_ITEM, 15, 2) == 0) {
+            if (iVar1 && FindEntityByID(PLAYER_ITEM, PLAYER_ITEM_SWORD_BEAM1, 2) == 0) {
                 CreatePlayerBomb(this, 0xf);
                 if (iVar1 == 0xf) {
                     gPlayerState.field_0xab = 5;
diff --git a/src/manager/manager22.c b/src/manager/manager22.c
index 4d6130cc..a8bb0794 100644
--- a/src/manager/manager22.c
+++ b/src/manager/manager22.c
@@ -159,7 +159,7 @@ void sub_0805BB74(s32 lightLevel) {
     }
     gArea.lightLevel = lightLevel;
     gRoomVars.lightLevel = gArea.lightLevel;
-    manager = (Manager22*)DeepFindEntityByID(9, 0x22);
+    manager = (Manager22*)DeepFindEntityByID(MANAGER, 0x22);
     if (manager) {
         Manager22_Main(manager);
         gScreen.lcd.displayControl |= DISPCNT_BG3_ON;
diff --git a/src/manager/manager36.c b/src/manager/manager36.c
index ca9c5c24..7dcf71c4 100644
--- a/src/manager/manager36.c
+++ b/src/manager/manager36.c
@@ -36,7 +36,7 @@ void CreateManager36(Entity* entity, ScriptExecutionContext* context) {
 }
 
 void DeleteManager36(Entity* entity, ScriptExecutionContext* context) {
-    Entity* manager = FindEntity(9, 0x36, 6, context->intVariable, 0);
+    Entity* manager = FindEntity(MANAGER, 0x36, 6, context->intVariable, 0);
     if (manager != NULL) {
         DeleteEntityAny(manager);
     }
diff --git a/src/manager/managerF.c b/src/manager/managerF.c
index f1cc1aca..1c3bd127 100644
--- a/src/manager/managerF.c
+++ b/src/manager/managerF.c
@@ -286,7 +286,7 @@ void sub_08059220(ManagerF* this) {
 
 void sub_08059278(void) {
     ManagerF* tmp;
-    tmp = (ManagerF*)FindEntityByID(0x9, 0xF, 0x6);
+    tmp = (ManagerF*)FindEntityByID(MANAGER, 0xF, 0x6);
     if (tmp) {
         sub_08058ECC(tmp);
     }
diff --git a/src/npc/bigGoron.c b/src/npc/bigGoron.c
index cb791a38..182b71f1 100644
--- a/src/npc/bigGoron.c
+++ b/src/npc/bigGoron.c
@@ -77,7 +77,7 @@ void sub_0806CF30(Entity* this) {
 }
 
 Entity* sub_0806D00C(Entity* this) {
-    Entity* entity = FindEntity(7, 76, 7, 0, 0);
+    Entity* entity = FindEntity(NPC, BIG_GORON, 7, 0, 0);
     if (entity != NULL) {
         this->parent = entity;
     }
@@ -100,7 +100,7 @@ void sub_0806D0B0(Entity* this) {
 }
 
 void sub_0806D0F8(void) {
-    Entity* entity = FindEntityByID(7, 0x4c, 7);
+    Entity* entity = FindEntityByID(NPC, BIG_GORON, 7);
     if (entity != NULL) {
         sub_0806D0B0(entity);
     }
@@ -359,22 +359,22 @@ void sub_0806D66C(Entity* this) {
 ASM_FUNC("asm/non_matching/bigGoron/sub_0806D67C.inc", void sub_0806D67C(Entity* this))
 
 void sub_0806D6D0(void) {
-    Entity* entity = FindEntity(7, 0x4c, 7, 2, 0);
+    Entity* entity = FindEntity(NPC, BIG_GORON, 7, 2, 0);
     if (entity != NULL) {
         entity->subAction = 2;
     }
-    entity = FindEntity(7, 0x4c, 7, 1, 0);
+    entity = FindEntity(NPC, BIG_GORON, 7, 1, 0);
     if (entity != NULL) {
         entity->subAction = 1;
     }
 }
 
 void sub_0806D70C(void) {
-    Entity* entity = FindEntity(7, 0x4c, 7, 2, 0);
+    Entity* entity = FindEntity(NPC, BIG_GORON, 7, 2, 0);
     if (entity != NULL) {
         entity->subAction = 0;
     }
-    entity = FindEntity(7, 0x4c, 7, 1, 0);
+    entity = FindEntity(NPC, BIG_GORON, 7, 1, 0);
     if (entity != NULL) {
         entity->subAction = 0;
         entity->spriteSettings.draw = 3;
@@ -382,22 +382,22 @@ void sub_0806D70C(void) {
 }
 
 void sub_0806D74C(void) {
-    Entity* entity = FindEntity(7, 0x4c, 7, 2, 0);
+    Entity* entity = FindEntity(NPC, BIG_GORON, 7, 2, 0);
     if (entity != NULL) {
         entity->subAction = 3;
     }
-    entity = FindEntity(7, 0x4c, 7, 1, 0);
+    entity = FindEntity(NPC, BIG_GORON, 7, 1, 0);
     if (entity != NULL) {
         entity->subAction = 2;
     }
 }
 
 void sub_0806D788(void) {
-    Entity* entity = FindEntity(7, 0x4c, 7, 2, 0);
+    Entity* entity = FindEntity(NPC, BIG_GORON, 7, 2, 0);
     if (entity != NULL) {
         entity->subAction = 4;
     }
-    entity = FindEntity(7, 0x4c, 7, 1, 0);
+    entity = FindEntity(NPC, BIG_GORON, 7, 1, 0);
     if (entity != NULL) {
         entity->subAction = 1;
     }
@@ -408,14 +408,14 @@ void sub_0806D7C4(Entity* this, ScriptExecutionContext* context) {
 
     this->x.HALF.HI = gPlayerEntity.x.HALF.HI;
     this->y.HALF.HI = gPlayerEntity.y.HALF.HI - 0x18;
-    entity = FindEntity(7, 0x4c, 7, 2, 0);
+    entity = FindEntity(NPC, BIG_GORON, 7, 2, 0);
     if (entity != NULL) {
         sub_0807DEDC(this, context, entity->x.HALF.HI, entity->y.HALF.HI);
     }
 }
 
 void sub_0806D804(Entity* this, ScriptExecutionContext* context) {
-    Entity* entity = FindEntity(7, 0x4c, 7, 2, 0);
+    Entity* entity = FindEntity(NPC, BIG_GORON, 7, 2, 0);
     if (entity != NULL) {
         this->x.HALF.HI = entity->x.HALF.HI;
         this->y.HALF.HI = entity->y.HALF.HI - 0x10;
diff --git a/src/npc/forestMinish.c b/src/npc/forestMinish.c
index ea0b9bb7..e31cb80d 100644
--- a/src/npc/forestMinish.c
+++ b/src/npc/forestMinish.c
@@ -1,6 +1,7 @@
 #include "npc.h"
 #include "object.h"
 #include "functions.h"
+#include "playeritem.h"
 
 extern void sub_080600F0(Entity*);
 extern void sub_08060158(Entity*);
@@ -215,7 +216,7 @@ void sub_08060318(void) {
     int i;
 
     for (i = 2; i >= 0; i--) {
-        ent = FindEntityByID(8, 2, 2);
+        ent = FindEntityByID(PLAYER_ITEM, PLAYER_ITEM_BOMB, 2);
         if (ent != NULL) {
             CreateDust(ent);
             DeleteEntity(ent);
diff --git a/src/npc/goronMerchant.c b/src/npc/goronMerchant.c
index 07f6117f..0aae9b37 100644
--- a/src/npc/goronMerchant.c
+++ b/src/npc/goronMerchant.c
@@ -83,7 +83,7 @@ void sub_08069660(Entity* this) {
 void sub_08069684(void) {
     Manager* mgr;
 
-    if (FindEntityByID(9, 0x31, 8) == NULL) {
+    if (FindEntityByID(MANAGER, 0x31, 8) == NULL) {
         mgr = GetEmptyManager();
         if (mgr != NULL) {
             mgr->type = 9;
diff --git a/src/npc/guardWithSpear.c b/src/npc/guardWithSpear.c
index ddb8ffde..8293f541 100644
--- a/src/npc/guardWithSpear.c
+++ b/src/npc/guardWithSpear.c
@@ -1,12 +1,13 @@
 #include "entity.h"
 #include "script.h"
 #include "player.h"
+#include "npc.h"
 
 ASM_FUNC("asm/non_matching/guardWithSpear/sub_0806407C.inc",
          void sub_0806407C(Entity* this, ScriptExecutionContext* context))
 
 void sub_08064180(void) {
-    Entity* entity = FindEntityByID(7, 0x15, 7);
+    Entity* entity = FindEntityByID(NPC, GUARD_1, 7);
     if (entity != NULL) {
         DeleteEntity(entity);
     }
diff --git a/src/npc/malon.c b/src/npc/malon.c
index 77d6a20c..2a3b2fa1 100644
--- a/src/npc/malon.c
+++ b/src/npc/malon.c
@@ -56,12 +56,12 @@ void sub_08065900(Entity* this) {
 void sub_08065914(Entity* this) {
     Entity* target;
 
-    target = FindEntityByID(7, 0x1F, 7);
+    target = FindEntityByID(NPC, EPONA, 7);
     if (target != NULL) {
         PositionRelative(this, target, Q_16_16(24.0), Q_16_16(-1.0));
         target->parent = this;
     }
-    target = FindEntityByID(7, 0x20, 7);
+    target = FindEntityByID(NPC, MILK_CART, 7);
     if (target != NULL) {
         PositionRelative(this, target, Q_16_16(40.0), 0);
         target->parent = this;
diff --git a/src/npc/pina.c b/src/npc/pina.c
index 5d49e1b3..3186f3ea 100644
--- a/src/npc/pina.c
+++ b/src/npc/pina.c
@@ -102,35 +102,35 @@ void sub_08063B68(Entity* this) {
 }
 
 void sub_08063C14(void) {
-    Entity* entity = DeepFindEntityByID(7, 0x14);
+    Entity* entity = DeepFindEntityByID(NPC, PINA);
     if (entity != NULL) {
         InitAnimationForceUpdate(entity, 8);
     }
 }
 
 void sub_08063C2C(void) {
-    Entity* entity = DeepFindEntityByID(7, 0x14);
+    Entity* entity = DeepFindEntityByID(NPC, PINA);
     if (entity != NULL) {
         InitAnimationForceUpdate(entity, 4);
     }
 }
 
 void sub_08063C44(void) {
-    Entity* entity = DeepFindEntityByID(7, 0x14);
+    Entity* entity = DeepFindEntityByID(NPC, PINA);
     if (entity != NULL) {
         InitAnimationForceUpdate(entity, 0);
     }
 }
 
 void sub_08063C5C(void) {
-    Entity* entity = DeepFindEntityByID(7, 0x14);
+    Entity* entity = DeepFindEntityByID(NPC, PINA);
     if (entity != NULL) {
         InitAnimationForceUpdate(entity, 9);
     }
 }
 
 void sub_08063C74(void) {
-    Entity* entity = DeepFindEntityByID(7, 0x14);
+    Entity* entity = DeepFindEntityByID(NPC, PINA);
     if (entity != NULL) {
         CreateSpeechBubbleExclamationMark(entity, 8, 0xffffffe8);
     }
diff --git a/src/npc/rem.c b/src/npc/rem.c
index 392c8198..8c2c98f8 100644
--- a/src/npc/rem.c
+++ b/src/npc/rem.c
@@ -309,7 +309,7 @@ void sub_0806AB74(Entity* this) {
 }
 
 void sub_0806AB9C(Entity* this, ScriptExecutionContext* context) {
-    Entity* entity = FindEntity(7, 0x37, 7, 1, 0);
+    Entity* entity = FindEntity(NPC, REM, 7, 1, 0);
     if (entity != NULL) {
         DeleteEntity(entity);
     }
diff --git a/src/npc/zelda.c b/src/npc/zelda.c
index 90222873..46187a72 100644
--- a/src/npc/zelda.c
+++ b/src/npc/zelda.c
@@ -30,7 +30,7 @@ void sub_08066CF8(Entity* this) {
 }
 
 void sub_08066D04(Entity* this) {
-    this->parent = DeepFindEntityByID(7, 0x2E);
+    this->parent = DeepFindEntityByID(NPC, ZELDA_FOLLOWER);
 }
 
 void sub_08066D14(Entity* this, ScriptExecutionContext* context) {
@@ -85,7 +85,7 @@ void sub_08066D94(Entity* this) {
 void SetZeldaFollowTarget(Entity* this) {
     Entity* pEVar1;
 
-    pEVar1 = DeepFindEntityByID(7, 0x2E);
+    pEVar1 = DeepFindEntityByID(NPC, ZELDA_FOLLOWER);
     if (pEVar1 != NULL) {
         CopyPosition(this, pEVar1);
         sub_080686C4(this, pEVar1);
diff --git a/src/npcUtils.c b/src/npcUtils.c
index bf609c86..1fabfe67 100644
--- a/src/npcUtils.c
+++ b/src/npcUtils.c
@@ -34,7 +34,7 @@ void sub_0806EC20(Entity* ent) {
 }
 
 void sub_0806EC38(void) {
-    Entity* e = FindEntityByID(7, 0x58, 7);
+    Entity* e = FindEntityByID(NPC, NPC_UNK_58, 7);
     if (e != NULL)
         DeleteEntity(e);
 }
diff --git a/src/object/book.c b/src/object/book.c
index c0003115..3cea262b 100644
--- a/src/object/book.c
+++ b/src/object/book.c
@@ -2,6 +2,7 @@
 #include "functions.h"
 #include "message.h"
 #include "item.h"
+#include "npc.h"
 
 extern void (*const BookActionFuncs[])(Entity*);
 extern s8 const gUnk_08123D94[];
@@ -152,7 +153,7 @@ void sub_0809B5EC(Entity* this) {
         switch (this->subAction) {
             case 0: {
                 Entity* parent;
-                parent = FindEntityByID(7, 26, 7);
+                parent = FindEntityByID(NPC, STURGEON, 7);
                 if (!parent) {
                     return;
                 }
diff --git a/src/object/greatFairy.c b/src/object/greatFairy.c
index a0e29797..a03d9344 100644
--- a/src/object/greatFairy.c
+++ b/src/object/greatFairy.c
@@ -517,7 +517,7 @@ void sub_080873FC(void) {
     SoundReq(SFX_APPARATE);
     gRoomControls.camera_target = NULL;
 
-    while (ent = FindEntityByID(0x6, 0x1b, 0x6), ent != NULL) {
+    while (ent = FindEntityByID(OBJECT, GREAT_FAIRY, 0x6), ent != NULL) {
         DeleteEntity(ent);
     }
 }
@@ -546,7 +546,7 @@ void sub_08087424(Entity* this, ScriptExecutionContext* context) {
 void sub_0808747C(Entity* this, ScriptExecutionContext* context) {
     u32 iVar1 = 0;
 
-    iVar1 = (u32)FindEntity(0x6, 0xf, 0x6, 0xb, 0x0);
+    iVar1 = (u32)FindEntity(OBJECT, SPECIAL_FX, 0x6, 0xb, 0x0);
     if (iVar1 != 0) {
         iVar1 = 1;
     }
diff --git a/src/object/object6A.c b/src/object/object6A.c
index 0d2fb68e..2b655443 100644
--- a/src/object/object6A.c
+++ b/src/object/object6A.c
@@ -195,7 +195,7 @@ void sub_08094B94(Object6AEntity* this) {
 }
 
 void sub_08094BE0(Entity* this) {
-    Entity* e = FindEntity(6, OBJECT_6A, 6, 0x22, 0);
+    Entity* e = FindEntity(OBJECT, OBJECT_6A, 6, 0x22, 0);
     if (e != NULL) {
         CopyPosition(&gPlayerEntity, e);
         e->z.HALF.HI = -12;
@@ -257,14 +257,14 @@ void sub_08094CDC(Object6AEntity* this) {
 }
 
 void sub_08094D10(Object6AEntity* this) {
-    Entity* e = FindEntity(6, 0x6a, 6, 3, 98);
+    Entity* e = FindEntity(OBJECT, OBJECT_6A, 6, 3, 98);
     if (e != NULL) {
         e->action = 0xFF;
     }
 }
 
 void sub_08094D34(Object6AEntity* this) {
-    Entity* e = CreateObject(0x6a, 0x15, 0xd);
+    Entity* e = CreateObject(OBJECT_6A, 0x15, 0xd);
     if (e != NULL) {
         e->x.HALF.HI = gRoomControls.origin_x + Q_8_8(1.0);
         e->y.HALF.HI = gRoomControls.origin_y + Q_8_8(2.345);
@@ -273,7 +273,7 @@ void sub_08094D34(Object6AEntity* this) {
 }
 
 void sub_08094D70(Object6AEntity* this) {
-    Entity* e = FindEntity(6, 0x6a, 6, 0x15, 0xd);
+    Entity* e = FindEntity(OBJECT, OBJECT_6A, 6, 0x15, 0xd);
     if (e != NULL) {
         e->action = 0xFF;
     }
@@ -306,7 +306,7 @@ void sub_08094DD8(Object6AEntity* this) {
 }
 
 void sub_08094E0C(Object6AEntity* this) {
-    Entity* e = FindEntity(6, 0x6a, 6, 4, 0);
+    Entity* e = FindEntity(OBJECT, OBJECT_6A, 6, 4, 0);
     if (e != NULL) {
         e->action = 0xFF;
     }
@@ -483,7 +483,7 @@ void sub_08095120(Object6AEntity* this) {
 }
 
 void sub_08095164(Object6AEntity* this) {
-    Entity* e = FindEntity(6, 0x6A, 6, 8, 0);
+    Entity* e = FindEntity(OBJECT, OBJECT_6A, 6, 8, 0);
     if (e != NULL) {
         InitAnimationForceUpdate(e, 3);
     }