I was going to suggest Bubsy naturally since it is the most AWESOME platformer for the Jaguar. Yeh yeh, I know, he can't help it.
All kidding aside (since that above was my Bubsy impersonation) you already have that game, and with some practice it can be a really fun game.
Umm... can't suggest Pitfall enough. That game is VERY underrated. My favs have turned out to be: Bubsy (but it has a steep learning curve so be warned), Cybermorph (it grows on you), Tempest 2K (awesome), Doom (Amazing... try two player mode sometime though it is not perfect), and RAIDEN (good shoot em up.)
Wolfenstein 3D is a fun game and recently touted by the developer to be his favorite version.
Aside from that, see if you can get a rom loader of some type, or BJL solution. There are a lot of fun fan made games out there. (Kobashi Maru, Surrounded, Tetris, Pacmania, etc.)