Finally hitting the letter "D" and also #200. (Note that I skipped "Dalek" because unlike E.T.'s species, there's no evidence that it was ever intended they were really inhabitants of the Star Wars galaxy-they're just an easter egg.)
191. Crokes. Crokes are tiny invertebrates (never larger than the hand of a large individual such as a Wookiee) who are reputed to resemble three-legged hairy snails or slugs. They're naturally aggressive and acquisitive despite this, and will apparently ruthlessly eliminate others who stand in the way of their personal gains. This lead to the Crokes suffering greatly when they made war on each other using large, carnivorous, and none-too-picky fast-breeding creatures, apparently all but destroying their populations on many of their worlds.
How, you are probably asking, did they manage to get many worlds if they're so tiny? Apparently, at least part of it comes from the fact that they could pretend to be much bigger than they actually were using Force-based techniques (Lando Calrissian Adventures villain Rokur Gepta was actually a Croke), and they may have naturally had extremely long lifespans, which would presumably be very useful in long-term plotting. How long? Rokur Gepta was 20,000 or so years old when he died of severe injuries (said severe injuries involving Lando Calrissian grabbing him and squeezing until he went squish).
Rating: 5/5. The Crokes are more implausible than a lot of Star Wars species, but in a good way-isn't it a hilarious thought that these teeny tiny things would be scheming and trying to take over planets and whatnot? (And are pretty good at it, considering?)
192. Crotok. Sapient. Alien. A species.
Rating: 0/5. AAARRRGGHHH.
193. Cthon. Cthon are basically H.P. Lovecraft-style ghouls who live on Coruscant, deep in the ground-level areas that are almost inaccessible. Some were goaded into attacking Darth Vader once. It did not end well for them.
They may have gone extinct during the Yuuzhan Vong invasion, since those jerks wrecked the place and filled it with their own preferred brands of horrible roving predators and such.
Rating: 4/5. They're pretty amusing, and more logical than their Lovecraft fiction counterparts (if the entire planet is a city and has been for millennia, it's a bit more plausible that there would be creatures like them). Ironically, there's a somewhat similar probably nonsapient species called corridor ghouls that live in the same areas.
194. Cuvacians. Cuvacians apparently have a difficult-to-translate language, because an advertiser for a translation device used their language as an example of what it could translate.
Rating: 2/5. Establishing some languages as harder to translate than others makes sense, I suppose.
195. Cyborreans. They're from Cyborrea, which is in Hutt Space. They breed Cyborrean Battle Dogs, also known as neks, which do not so much resemble dogs as tiny reptilian hippos with gland problems. Neks are frequently used as hunting and attack creatures, as they are designed to be highly resistant to weapons and stuff. They're also apparently illegal in most of the galaxy.
Rating: 3/5. I suppose it wouldn't be timely to make a Michael Vick joke at this point... Whoops.
196. Cyrillians. Reptilian guys as tall as Wookiees, they invented the DUM pit droids, those little saucer-headed robots that had all those crazy antics in Episode I.
Rating: 2/5. Eh, I liked those pit droids, although I'm sure plenty of other people didn't.
197. D'farians. The D'farians protected the Bothans during the Caamas Document crisis.
That's about it.
Rating: 2/5. Minimal information, sure, but the fact that they protected the Bothans, who were at rock-bottom in terms of popularity at that particular moment, is an intriguing suggestion of possible traits of their culture.
198. Dabi. All we know is that one of them had purchased a droid to serve as a waiter, and that droid was extremely obnoxious, leading to the owner praising a Mandalorian (who happened to be Boba Fett's granddaughter-yes, really) who destroyed its voicebox with a blaster.
Rating: 2/5. At least it's an amusing incident, but it tells us nothing about the Dabi.
199. Daimlo. Daimlo come from Daimla. (Ha!) They're fat, are probably short, have long horns and faces (although they don't resemble the Iktotchi beyond their horns, despite what the article says), and are among the species known for podracing.
Rating: 2/5. Amazing how there's a decent amount of of information there, but it says almost nothing as a whole (except that they're really ugly-my observation from the page picture, not Wookieepedia's).
200. Daltarri. They're plant things who look amusing. They apparently don't like it when their allies question them about aiding them (their allies aiding the Daltarri, that is).
Rating: 3/5. I'm not entirely sure what their cultural feature means and attempting to convey the meaning of the sentence that describes it is driving me batty, but it's there and they made an effort. Plus they look amusing.