In the UK , it is mainly the Scottish resorts that allow pets. I was going to mention Loch Rannoch as we stayed there and saw a few people there with dogs.
In the UK, in the RCI Points system, RCI also offers exchanges into private accommodation - cottages, houses, etc - some of these will allow pets (it will sometimes say in the description). But they are usually offered in the Autumn months and perhap early Spring.
Sue