Torlundy “death tracks” are great if you like super steep, loamy trails, Alt-a Mhulin is also a cool trail that comes down to near the 10 under route. Generally speaking, any random trail through the woods at Nevis Range will be pretty good and usually rooty/techy/steep rather than the typical dodgy jumps built by kids in many woods.
Kinloch is also decent, bit more rocky and not too slippy in the wet, save for near the dam.
There’s some decent stuff in Glenloy, I think, but it’s yonks since I’ve ridden there.
Stob bàn often gets mooted as a good ride but we found it to be pretty naff for the bottom three quarters, and thus on a smiles-per-mile it basis it gets outshone by a lot of other local routes IMHO.