It's interesting to see how many islands can be large enough to have people living on them.Ordanance Survey wrote:Great Britain is an island in its own right, but aside from the mainland, there are hundreds of islands around the British coast, many uninhabited*. Inspired by David Garcia’s data visualisation of the Philippines, our GeoDataViz team worked with Alasdair Rae at the University of Sheffield to explore Britain’s largest islands.
They found that there are 82 English, Scottish and Welsh islands larger than 5km2. Scotland boasts the vast majority with 71, not surprising when you consider the Outer Hebrides, Shetland and Orkney and other beautiful islands off the coast. Wales had just 2 entries and England 9.
You might want to go look for more information on any of the islands that interest you. You could probably sneak one or two into a D&D campaign without anyone noticing.
I've been looking to see how many are solid enough to work as Spelljammer asteroids.