HERE is a link to a post with compatibility chart of Sigma lenses.
This suggests that, via the adapter, these lenses will function as one would expect a native lens to behave. There are a couple of interesting lenses on the list. The 120-300 F2.8. I had one for my Canon and its a great lens. If the adapter makes it function as a native E mount lens its a really compelling option. I still have the two matching Sigma teleconverters. I wonder if they would work as well as they did on the Canon?
120 2.8 to 600 F5.6 is a nice range.