There are currently about 1,870 condominium plans registered in Toronto. They are numbered sequentially as they are registered. I'm sure the majority of these are residential, but this number also includes industrial condominiums (fairly common in Scarborough especially) and a few office and commercial condominiums.
How many have over 50 units? I'm not sure, and the only way I can think of at the moment to find this information would be to pull out the plans for each condo at the Land Registry Office. That would be a long and tedious job. You might ask at the Land Registry Office if anyone keeps such statistics, but I don't know that they do, or why they would.