Ancestry have released the digitised images of the Canadian 1921 census. They aren’t indexed yet so searching has to be conducted the “old” way – page by page. Like many English researchers I have ancestors who got on a boat for a whole variety of reasons and traded England for Canada. Again like others some of mine stayed and their descendants are still there whilst others decided that the wide open spaces of Canada wasn’t for them and returned.
These records will be indexed in the fullness of time, but if you know approximately where your Canadian ancestors might have been living in 1921 then you will enjoy browsing these records.