I love Critters for SR3. I know it's been out forever as a free PDF, but I figured I should go through and review stuff.
Critters has everything you need to put, well, critters in SR3. If you've ever wanted to fight dragons, bears, and more, get this. You can set a trap for players pretty easily when they discover cyborg or awakened paranimals staring at them from the other side of a chain link fence. Especially the kind that breathe fire.