In Canada Beech 18s on floats were quite common, including post war built aircraft. There are still a few around. Bristol Aircraft in Winnipeg made the transition from military to civil production making these floats.
Depending on your definition of "post war", several ex RCAF Cranes (Cessna Bobcat to the yanks) wound up on floats. Like most post war Cranes, they dissolved in the Canadian weather over a few years.
Canadian Aircraft Products, who made Twotter floats in Richmond, BC used to have a very nice model in their lobby of a Dash 7 on floats, but it never made it past the model stage.
In immediate post war Canada if you needed a larger seaplane you used surplus Cansos, Geese, Widgeons, etc. These handled much better on the water than big float planes. By the time these wore out every remote community in Canada had a big enough runway for things like a Dakota, an Avro 748, a Convairliner, etc.