Toronto is pretty photogenic. You can get great shots of downtown Toronto's skyline at these spots (or just for a great view and not necessarily for photography):
1. The Centre Island. You need to take a ferry to get there, but the ferry is pretty cheap (CAD$7.5 there and back).
2. The One Eighty (https://www.the51stfloor.com). This is a restaurant on top of the Manulife Centre at (55 Bloor Street West) and it has a great terrace on the top of the building directly facing the financial district skyline. The restaurant does cost money and it can get pretty busy on weekends and in the summer.
3. Riverdale Park East. It's a public park so it's free.
4. CN Tower. It costs quite a bit of money to go up there. If you eat at the restaurant on top (called 360), then the admission to the tower is free.
There are likely a lot of other places that I've missed, but these 4 are the ones that I personally like a lot.