What are the effects and the like of the different mutagens?

 Out of curiosity, I made a character with max cooking to see the different types of mutagen. There are a lot you can make in any case. But I don't know which one I'd want to make if I don't know what they do at all! I can get an idea of what each type of mutagen would do but I've hardly delved much into ACTUALLY doing mutagen before. I simply have always worked more on other things since getting high cooking is simply annoying.
 I'd like to have some sort of focused direction to go with mutations, sounds like I can be a spider-plant guy, but what would that do? But in the end those two options may give me bonuses that I don't care much about. And mutagen is a pain to get in any case, so I'd like to just make it easier and know the possibilities beforehand.
 I can live with bad effects, it is my choice to risk mutagen after all, but some 'good' effects I don't care about much. For example: I almost never go 'swimming' or near those areas, just cuz I don't care to, so why would I need the 'gills' mutation? I'm a fist fighter so claws would be better.

The wiki [link] has a page that lists the mutations and their respective trees, and it’s fairly up to date. It also gives a short rundown of each tree and what it’s best for, but don’t take what it says as the gospel truth. Experiment with different trees, figure out what’s right for you/your situation.

 That stuff is pretty cool, is it possible to have a 'second' mutation tree, simply one that isn't pass the threshhold? I think I'd like plant as a focus but I'd like a secondary mutation line if possible.

 EDIT: Also, is it possible to get only good mutations? Or is it a 100% you'll get it at some point. (Not including if you ALREADY have all the good options) I dislike save scumming, but some of the possibilities I'm just like "Ya right, I'm totally gonna die if I get that" :P Of course I'll keep most of the bad ones cuz I don't like cheating, but in terms of mutations that make people dislike you, most of them tend to be dead. So doesn't really matter anyway! Even boosting up the NPC rate a bit still can keep them rare.

I believe it’s possible to have mutations from a different tree while still also having post-thresh mutations in one tree. However, the more mutations you have from one tree the more likely you’ll get more mutations from that same tree, so it might be more difficult once you’re that far along in the progression.

Robust Genetics helps a lot with getting good mutations, but in the end there’s no way to guarantee you won’t get at least a few bad mutations. That’s why trees like Alpha are balanced because of their low risk low reward system versus something like Chimera or Slime which gives some great mutations in exchange for some serious disabilities.

 Haha, ya. "Oh ya, you can be immortal from enemies, but you'll die in your sleep from decomposing. Or you'll kill all your friends and family from radiation!"
 I feel like some of the options really need some changing, although it does make sense that there are possible side effects. Does vomit act as a ranged attack or something? Also, how would some of the other attack things like a tail and claws go into place? I'd hate to keep activating the ability EVERY TIME I wanted to use it. Also, I have a tendency to not used melee weapons other than my fists anyway. Muay thai is crazy powerful with high strength and it is just like WRECK EVERYTHING! But I hope that things like nail knuckles would still work with fist-damage mutations. Claws + high strength + Muay Thai + high unarmed skill + nail knuckles would be like 1 shotting all of the basic-ish enemies. "Oh hello zombies horde" *One shots everything but a brute*

Embrace the slime. Love the slime. Become the slime. Slime is best mutation tree.

Be one with the elves. Unlike the majority of DF elves Cata elves are actually cool.

Chimera is good if you can get expanded digestive system and recycler unit cbm, then the main downside of the mutation tree is pretty much solved and you become a monster in combat.

They do! Nail knuckles are treated as weapons that simply use the unarmed skill, and don’t function like gloves which would block your claws.

They halve the damage output, though.
Claw damage happens if you’re wielding an unarmed weapon (“none” counts as unarmed). You get half claw damage for having a free left hand and half claw damage for having free right hand AND no weapon wielded.