Colorado Cowboys- This name goes along with the western/rodeo theme in Denver, and it would go well with the Bandits and Wranglers. Hmmm, I wonder who would pick them...cough...Jam...cough
Louisville Legends- Lots of Louisville's history is associated with some pretty legendary things, Muhammad Ali, Louisville Slugger bats, and Kentucky's history of success in basketball.
Detroit Cougars- This one might need a vibe check as it was previously the name of the Detroit Red Wings. I think it fits well with the classic names in Detroit, Tigers, and Lions.
Minnesota Galaxy- This was a rejected name for the Timberwolves, and it really works with the Northern Lights/North Stars theme in MN.
Seattle Summit- I know someone else already suggested this for Denver, but I feel that it fits better with Seattle and the Pacific Northwest with the evergreen trees and mountains in the area. This was also my Seattle suggestion for the AltFL.
Chicago Jokers- I took inspiration from the famous card game "Chicago." I feel this theme would be a lot of fun to work with as well, should it get picked.