Good to know. (owo)-b I assume editing/recolouring/splicing your sets is okay, too?
As for suggestions, I have a few ideas that I think would be cool/useful to me and other game-makers:
- Seaside and coastal set, for making beaches/undersea maps;
- Swamp and marsh set, with a foggy, mossy, decayed look;
- Horror/creepy set with graves, skulls, haunted house elements;
- Modern interior/exterior sets to match the modern items in the icon sets (RTP is very generic fantasy medieval flavoured).