Yes we have Toronto FC. Typically close to a sellout crowd of about 22,000
We also have Maple Leafs, Blue Jays and Raptors
The CFL Argos are not well supported in large part because as the 4th largest city in North America, Toronto sees itself as Major League sports town and views the CFL as Minor league.
I don't really want to see NFL here but if it came (not 1 game per year) I'm sure it would sell out most games.