The smoking area at every venue can be good for meeting people with a bad habit. ๐
Smaller live music events potentially. Promise Cherry Beach during the summer for example.
Events happening at university campuses such as UofT St George.
BlogTO used to be a decent source of things happening. Not sure if it still is.
In general I'd ask what sort of people I'd like to meet, figure out what events they attend and then attend those kinds of events.