Of special interest to SP players, the Royal Collections Trust has released online the collection of George III maps, especially good for AWI and the 45, but covering locations from Malaya to South America.
There are some excellent finds such as the OOB for Prestonpans.
https://militarymaps.rct.uk/This allows you to go to a google map with markers indicating all the maps available. I only scratched the surface but on the face of it, a great resource, and the maps themselves are marvellous curiosities.