For Quebec as a whole, it's hard to pick.
I'd say that no human settlement in province is prettier on the whole than Quebec City is, but it's way above the threshold of the thread as it has hundreds of thousands of people.
In terms of smaller places, one thing I've found in thinking about this thread is that a lot of them look the same. You typically have a large, imposing Catholic church (often stone) in the centre, surrounded by a number of heritage buildings related to the church (like the presbytère, where the priest would live). Often there are also large old college or seminary-style buildings with classic architecture. Then you have a cluster of old French-style homes in the mansarde style, or in the Canadi
en (Québécois) style with prominent sloping roofs that were developed by the colonists in response to heavy snow collapsing flat roofs.
Whether a town or village is pretty or not is generally dependent on how much of this stuff it has (and its geographic setting), but generally it's mostly the same vernacular repeated in every community.
In terms of towns, I do like St-Sauveur, north of Montreal in the Laurentians (it's actually become something of a resort suburb of the city):
https://www.google.com/search?q=sain...A_enCA931CA931
Baie-St-Paul is a bit further afield in the Charlevoix region, northeast of Quebec City:
https://www.google.com/search?q=baie...ih=577&dpr=1.5
Technically speaking Mont-Tremblant is probably the prettiest small town in Quebec (and even a bit beyond) but it was built from scratch to look like this, so not sure that it counts:
https://www.google.com/search?q=mont...A_enCA931CA931