A pretty basic Palette editor for the Sonic dissembles (or any other Genesis game with the same color format) Click anywhere on the project to open a prompt to edit the data imported.
I guess I should explain for the people wondering: Basically, the colors are stored as a shorthand hex color code, with each being 2 bytes, the first nibble is only there for padding, the second one is the blue, third green, and finally the fourth which is red. Simple enough if you understand the terms I was talking about lol.