I've only really used one commercial pattern, but there are quite a lot of other patterns out there.
The Green Pepper
The Green Pepper sells a racing
suit pattern, number 408 (pictured right), in their Patterns for Adults
section. I made several variations on this before I started trying to draft my
own patterns, and I can thoroughly recommend it. It's a four-panel unisex
pattern for four-way stretch athletic spandex.
I don't have any experience of Jalie's catsuit pattern, but it's been recommended by a correspondant who concurred with Kwik-sew's large sizes. Apparently there are more interesting patterns at Jalie, and they're multi-sized.
Kwik-sew have quite a number of women's catsuits and bodysuits in the women's activewear section, and publish a women's activewear book too. They have a wetsuit (UV suit) 2335 and a leotard (dancewear) 3029 in their men's section. They seem fair, although a sleeve for the wetsuit proved to be drafted far too large at the shoulder (like they'd mixed the thigh up with the arm), so I'm a little suspicious of them.
I've since had a lady write and say that she's always found their sleeves to be consistently too large, while the bodies are fine, so she disregards the sleeves. She also recommends against #3052 as 'just a large baggy fit in general' and unsalvageable. I wonder that nobody's complained about their sleeves to them.
... So I've just emailed them. See how they respond.
Nevtex seems to be mainly a fabric retailer, but their website has some catsuit/leotard patterns in the 'Dressmaking Aids' section of their site. I haven't tried them.
Simplicity, Vogue, etc
I don't know much about these. I've made a Simplicity top and some shorts, the instructions for the latter were rather unclear.