@In Flames it's more of a rough debug prototype based on the GB Tetris Attack (it uses that version's Panel graphics, I'm guessing since it was developed for GB hardware and then moved to GBC later), and even then only Lip's graphics are used in that; all the other characters and the actual background/border graphics are unused. All of this was buried super deep in the ROM, and there's still a fair bit more besides the characters that aren't here.
I think Lip's sprites still belong in the unused section regardless because you have to trigger an error screen and then use an obscure code to run a bootstrap program and most people will never see it.

The Panel de Pon sprites are technically used.
When you enter a cheat code on the title screen, the game switches to a GB port of Panel de Pon hidden inside.

@Deep Weeb Not like the publishers have given a choice, eh? Think about what you say before you say it.

It's a bit sad if you think about it how Panel de Pon it's such a great game but westerners would't even touch it if it's not hidden under another IP's coat of paint.

Why is there not Panel de Pon GB sprites here? The game is technically part of this game... Someone should rip the sprites, then either put it in this/a new section.