The only other Creatures game I mod a lot is C2, so I might as well list a few from there. I don't use as many cobs for it as I do DS. I often use the desert and volcano garden mods though, to give my creatures more spaces to live it. I also use the golden tomatoes and rainbow peppers to give my norns more to eat. For breeds, I love using the Albian Greys, Gargoyle Norns, Draco Norns, Kimahri norns, and Cat Norns. I don't use the genomes that come with those breeds though. I just change the breed slots in a default Akamai Canny norn and call it good. I never learned which breed had which genome, and don't really care enough to compare genomes and find out.
As for pet peeves, I have one major one. Most of the existing portable door agents are terrible, but I'm forced to use them in some of my larger wolfling runs. With most of them, creatures end up bouncing between the doors. They eventually get to where they want to be, but only after playing door roulette. It's frustrating when you want to string metarooms together and the poor creatures bounce between the rooms until they get exhausted and sleep. It doesn't ruin wolfling runs, but it's seriously annoying. Even the door agent I made a few months ago doesn't always work properly, and I can't figure out why. So whenever I get enough time, and more importantly motivation, I'm going to create a portable door that just... works.
What I'd really love to see are more tutorials though. I forget who said it but developers are the lifeblood of the community. Maybe if we had some tutorials or coding tear downs like on the Creatures Wiki, it wouldn't be so intermediating for newbies. A part of the reason it took me so long to really dive into caos was that I didn't know where to go after basic toys and vendor tutorials. I know I'm going to start commenting on why and how I made my agents the way I did, if I can get everything in order. That way there are a few more examples floating around for people to learn from. And, who knows, maybe some of my useless buttons can inspire someone to tweak my code a bit and dive into caos.