We don't really need single pictures of enemies. Sometimes the only good shots of them are group shots. A few of the ones you mentioned also seemed to be pretty good in quality.
Here's what I can do:
Beezo, Fryguy, Mouser, Hoopster, Phanto, Pidgit (maybe), Rocky Wrench, and maybe the SMW ones.
BTW do you know which episode I could find a normal Tweeter in? Tell me and I'll look.