diff --git a/constants/scgb_constants.asm b/constants/scgb_constants.asm
index 0f1814b08..0e923342c 100644
--- a/constants/scgb_constants.asm
+++ b/constants/scgb_constants.asm
@@ -125,6 +125,7 @@ SCGB_DEFAULT EQU $ff
 	const PREDEFPAL_UNOWN_PUZZLE
 	const PREDEFPAL_GAMEFREAK_LOGO_OB
 	const PREDEFPAL_GAMEFREAK_LOGO_BG
+NUM_PREDEF_PALS EQU const_value
 
 ; SGB system command codes
 ; http://gbdev.gg8.se/wiki/articles/SGB_Functions#SGB_System_Command_Table
diff --git a/engine/gfx/color.asm b/engine/gfx/color.asm
index b6d1a2b2e..af7b7cd3d 100644
--- a/engine/gfx/color.asm
+++ b/engine/gfx/color.asm
@@ -1170,7 +1170,9 @@ INCLUDE "gfx/sgb/pal_packets.asm"
 INCLUDE "data/sgb_ctrl_packets.asm"
 
 PredefPals:
+	table_width PALETTE_SIZE, PredefPals
 INCLUDE "gfx/sgb/predef.pal"
+	assert_table_length NUM_PREDEF_PALS
 
 SGBBorderMapAndPalettes:
 ; interleaved tile ids and palette ids, without the center 20x18 screen area
diff --git a/engine/pokemon/mail_2.asm b/engine/pokemon/mail_2.asm
index 634d5c69d..e0eb014b8 100644
--- a/engine/pokemon/mail_2.asm
+++ b/engine/pokemon/mail_2.asm
@@ -11,6 +11,7 @@
 	const BLUESKY_MAIL_INDEX ; 7
 	const MUSIC_MAIL_INDEX   ; 8
 	const MIRAGE_MAIL_INDEX  ; 9
+NUM_MAIL EQU const_value
 
 ReadPartyMonMail:
 	ld a, [wCurPartyMon]
@@ -126,6 +127,7 @@ ReadAnyMail:
 
 MailGFXPointers:
 ; entries correspond to *MAIL_INDEX constants
+	table_width 3, MailGFXPointers
 	dbw FLOWER_MAIL,  LoadFlowerMailGFX
 	dbw SURF_MAIL,    LoadSurfMailGFX
 	dbw LITEBLUEMAIL, LoadLiteBlueMailGFX
@@ -136,6 +138,7 @@ MailGFXPointers:
 	dbw BLUESKY_MAIL, LoadBlueSkyMailGFX
 	dbw MUSIC_MAIL,   LoadMusicMailGFX
 	dbw MIRAGE_MAIL,  LoadMirageMailGFX
+	assert_table_length NUM_MAIL
 	db -1 ; end
 
 LoadSurfMailGFX:
diff --git a/engine/pokemon/stats_screen.asm b/engine/pokemon/stats_screen.asm
index 4c351ff91..932c0f72b 100644
--- a/engine/pokemon/stats_screen.asm
+++ b/engine/pokemon/stats_screen.asm
@@ -570,9 +570,11 @@ StatsScreen_LoadGFX:
 
 .Jumptable:
 ; entries correspond to *_PAGE constants
+	table_width 2, StatsScreen_LoadGFX.Jumptable
 	dw LoadPinkPage
 	dw LoadGreenPage
 	dw LoadBluePage
+	assert_table_length NUM_STAT_PAGES
 
 LoadPinkPage:
 	hlcoord 0, 9
diff --git a/gfx/sgb/predef.pal b/gfx/sgb/predef.pal
index 233b25789..745767db7 100644
--- a/gfx/sgb/predef.pal
+++ b/gfx/sgb/predef.pal
@@ -1,4 +1,4 @@
-	RGB 31,31,31, 22,25,19, 16,21,30, 00,00,00 ; PREDEFPAL_00
+	RGB 31,31,31, 22,25,19, 16,21,30, 00,00,00 ; PREDEFPAL_ROUTES
 	RGB 31,31,31, 27,28,31, 15,20,31, 00,00,00 ; PREDEFPAL_PALLET
 	RGB 31,31,31, 24,28,19, 15,20,31, 00,00,00 ; PREDEFPAL_VIRIDIAN
 	RGB 31,31,31, 24,24,24, 15,20,31, 00,00,00 ; PREDEFPAL_PEWTER