I have been reading through the Midlands sandbox setting guide. It is a fantastically detailed resource for running a low magic world.
https://www.drivethrurpg.com/m/product/225936
The included monsters are not just the usual d&d ones and can adapt well to ICRPG, and the 50 modular adventures can be used to insert into a campaign or used as one shots, all with nice maps.