Tileset repoint
For those who want to mix graphics or draw their own without the tedious trouble of having to repoint, this patch repoints the palette, tile and tables of the first 15 tilesets into free space. Here's how it breaks down.

Palettes are in bank $B8 (1C0000), which was completely unused, taking up $B8:8000 through C400. Each palette has $400 bytes of space, which I'm fairly certain is more than it's possible to use with a palette.

Tables take up everything in bank $E0 through $E4 (300000-327FFF). They have about $2A00 bytes each, which is around $800 more than the largest table in the original (Which was Maridia at $21C5). Thus, I doubt you'd ever run out of space with even very complex tilesets.

Tiles take up $E5 through the first half of $EC (328000-364000). Each has $4000 bytes of space, $318 more than the largest tilesheet. It's not likely you'll end up out of space here, either.