As you know research says: Toronto companies post about 75% of their jobs on their own websites. That means company websites have three times more jobs than job boards and are your best source of employment agencies jobs. The research showed that more and more employment agencies jobs in all cities across Canada are being posted this way.

Tips for searching for Toronto area employment agencies: For example you want to find Toronto based employment agencies. Search. "employment agency" OR "casual labour" OR "temporary work" +Toronto

If you want to add in nearby cities use a search string like this:
"employment agency" OR "casual labour" OR "temporary work" +Toronto OR Mississauga OR Markham
Google-Homepages Only will find all the employment agency type companies in 3 cities at once.