I only use one, a Tokina 17mm f/3.5, its a great lens. I've had many other third party lenses and sold them all.
These Sigma or made by Sigma lenses would not AF on a Canon DSLR.
Quantaray 24mm f/1.8(made by Sigma),
Sigma 400mm f/5.6,
Sigma 105mm Macro (I paid $100 to Sigma to upgrade it, nice lens, but not when I have to pay Sigma to correct their design error)
Sigma 70-210mm f/4.5-5.6.
I kept them around to remind me that Sigma lenses may or may not autofocus in the future, if Canon tweaks their cameras AF system again.
Sigma 17-35mm (Cheap lens came with a used Canon XTi DSLR)
Tamron 28-80 (Cheap lens came with a used Canon XTi DSLR)
Tamron 75-300 (Cheap lens came with a used Canon XTi DSLR)
Tamron 200-500mm (OK lens, but difficult to use, even on a sturdy tripod, its so long it vibrates and must be used at high shutter speed.
Sigma 600mm mirror lens. (OK but not really useful to me)
Tokina 400mm f/5.6 (Great lens, but my 100-400mm L is better at over 10X the price I paid.)
Sigma 17-70mm (non OS) - (Stiff focus ring, poor IQ near mfd, otherwise excellent)
Samyang 14mm (absolutely the worst lens I've ever owned, a piece of junk. It went right bacl)
Various TC's by Sigma, Tamron, Quantaray, etc.
I'm sure there are more that I've forgotton.
I also have lots of old manual focus lenses by Hasselblad, Nikon, Mamiya, Pentax, Minolta, Olympus, and many more, along with adaptors so I can try them on my Canon DSLR. I am always buying old film cameras for the lenses, whenever I find one for too low of a price.