I have some Fiberology PA12+CF15 blend (link) from a long time ago and recently got around to using it. I am amazed to say the least! It prints easier than PETG, even without an enclosure. Only downside is that it is much more expensive per kg, although it is lower density so I don't seem to be going through it as quickly as other filaments.
I recently purchased some PC Blend with CF from Prusa as well. I haven't gotten to print it yet, but I've heard very good things about it, too.
What less common filaments do you fine folks like using?
eSun PA-HT CF - nylon and CF in a 290C extrusion temp mix. My biggest problem is that I've never managed to get the support settings right so supports tend to be structurally bonded to the part and require a dremel to remove.
The other is the eSun PA-LW, which I haven't found a good use for yet because it's so @#$@#%$%@ oozy that it pretty much only produces a decent part when in spiral mode. Makes fantastically light parts though.
I dusted off a sealed roll of polymaker natural ASA for my CR10 V2 pro, trying to print parts for my motorcycle and cars that were previously printed in PLA+. So far a few large parts have warped about 2/3rds of the way through. I purchased a PEI magnetic bed and am now using an enclosure. The benchy i printed looks perfect tho. If i can get it dialed in, i think it will be my favorite.