They're everywhere here, as it's a convenient way to express your politics and send a message. It can get tangly, like when we took down the Canadian flag from public buildings, or when the Province forbid the Labrador-only flag to be officially displayed on the Quebec border and they put it up anyway.
In the city you'll often see flags grouped together as one house expresses its views and neighbours respond. These displays can be pretty temporary. For example, English battle flags are almost never seen except on July 1, our Memorial Day, as backlash to all the Canada Day displays and festivities.
So there are five main flag options, and then their resulting combinations.
NL tricolour - nationalist. Usually displayed alone. Can be displayed with Labrador tricolour or Canada flag to indicate acceptance of the circumstances represented by those. Becomes less common as you head west across the island. Virtually unknown in Labrador.
Labrador tricolour - Dominant in Labrador. Displayed at every town hall, everywhere. It is universally their most revered flag, among whites, Metis, Innu, and Inuit.
Provincial flag - Dominant in rural areas of the island. Usually displayed with Union or Canadian flag, almost always at equal height.
Union flag - peppered everywhere, across island and in Labrador, in official and private capacity.
Canada flag - Found everywhere though less common as a private display in St. John's. Often displayed alongside any of the above.