I can find 4 for Thunder Bay:
Mac's branded;
Esso branded, former 7/11;
Brand new Esso branded location that replaced a Petro Canada,
and this was formerly a Spur/Husky.
Going "back in time",
this one had a Husky gas bar until a few years ago, and I think was originally a Spur store. This one had a Mac's branded gas bar and was formerly a 7/11.
This one was also a 7/11 with a gas bar, it's now a strip mall. (This location closed after an employee was nearly killed while defending a carton of cigarettes from a robber.)
There might be a couple others. About half of this city's gas stations have closed in the past decade, there's no money in it here because the margins are too small and the insurance for convenience stores is very expensive due to all of the injuries caused by employees trying to be heroes. One of the gas bar Mac's had an employee injured during a robbery, but they just spent a tonne of money rebuilding it about 5 years ago so I don't think it will close but might end up as something else. The stores can't keep owners, the one near me changes ownership about twice a year. It's an absolutely shitty investment from what I've heard from the people running them.
The owner of the Canadian Tire gas stations is loaded though. He doesn't own the stores themselves, just the gas stations, which are on separate properties and simply "near" Canadian Tire stores. Everyone else I've met who owns a gas station though says it's a shitty investment that makes almost no money.