Aspect Edit, which you can find on the wiki. And yep, it specifically edits Sonic 2, Chaos, and Triple Trouble. You can edit level layouts, tilesets, mappings, and palettes. But for Chaos and Triple Trouble, you'll need to locate the correct offsets for whatever you wish to edit. (I don't have everything split in my Sonic Chaos disassembly yet, and I think there's only been a few things documented in Triple Trouble but there is a hacking guide for Triple Trouble on the wiki, and bellow in my signature I have the link to the Sonic Chaos hacking guide.) Here's the link for Aspect Edit.