There also Front St in Port Credit. Port Credit and Streetsville both have a Queen St so there's TWO Queen Sts in Mississauga...
Other common street names in GTA/Hamilton/Oshawa (besides Toronto):
Church St
Streetsville, Brampton, Churchville (obviously), Oakville, Ancaster, Bowmanville, Newmarket, Maple, Richmond Hill, Markham, Georgetown, Acton, Waterdown, Aurora, Schomberg, Holland Landing, Bradford, Newcastle, Beaverton, Sunderland, Uxbridge
John St
Brampton, Cooksville, Burlington, Port Credit, Waterdown, Whitby, Oshawa, Milton, Orangeville, Acton, Hamilton, Kleinburg, Bradford, Georgetown, King City, Beaverton, Port Perry
James St
Hamilton, Burlington, Dundas, Waterdown, Milton, Georgetown, Streetsville, Bradford, Newcastle, King City, Beaverton, Uxbridge
Wellington St
Brampton, Hamilton, Dundas, Bowmanville, Aurora, Orangeville, Waterdown, Newmarket, Nobleton, Beaverton
Mill St
Streetsville, Brampton, Waterdown, Pickering Village, Oshawa, Richmond Hill, Thornhill, Dundas, Waterdown, Milton, Georgetown, Acton, Bolton, Stouffeville, Newcastle, Beaverton, Uxbridge
Elizabeth St
Port Credit, Brampton, Grimsby, Burlington, Whitby, Markham, Pickering Village, Thornhill, Milton, Orangeville, Beaverton
Victoria St
Milton, Georgetown, Churchville, Waterdown, Streetsville, Dundas, Stouffeville, Aurora, Uxbridge, Port Perry
Elgin St
Whitby, Oshawa, Bowmanville, Acton, Burlington, Waterdown, Dundas, Hamilton, Georgetown, Port Perry