Coming onto the list in the next year from Toronto:
Eau Du Soleil (699ft/213m)
Massey Tower (679ft/207m)
Those are the only 200m+ towers TO will be adding in the next year. We are running low on inventory

YC Condos might make the top 10 at some point at 198m, I imagine it could start construction by fall 2015.
In the medium term (2-5 years) I can see the Signature Towers coming on board though probably not for another 4-5 years. 480 University could start construction in as early as 2 years, Mirvish Towers are a wildcard but construction in 3-5 years is possible, then a possible office tower (Union, 156 Front, 45 Bay) would all easily be over 200m. Then there;s always a chance one of those Yorkville towers could get going in that time. As for 1 Yonge... there's another possibility there too. So there are more towers coming, TO will just be going through a lull for a 1-2 years as our big projects complete.