Basically, what feats can I use to get a Cohort, Animal Companion, Familiar, or something similar? Standard Class Features and ACF's not so much since they're very class specific, but if there are any noteworthy ones (particularly ones you get at low levels) feel free to list them as well. I know of several but the only one I know that will get me the critter I want is Leadership, and that is being left to RP. Of great interest are ways to earn this companion that wouldn't sound like Leadership.
Note: In a previous build idea the DM objected to Dragon Cohort, but soon after decided to let me take it but I'd have to RP getting the cohort in-game. It was a rather tentative ruling, and I'm not sure if something similar will happen again, but suggest away regardless.
Note2: I don't know if it matters, but we are allowed Pathfinder stuff for the most part, from what I can tell at least. So if there's something in PF that would prove relevant to this toss it in.