How about some grime VFX?
I find that VFX_DUR_PETRIFY makes some placeables look frost-encrusted in winter areas. How about something similar for dirt or slime?
Maybe something for ground cover, too?
Rather than make new placeables, it would be great to be able to "grime up" some or all of the existing ones.
It would be great if there were a reasonable colour match for existing tilesets and tile placeables, so that the placeables don't stand out like a sore thumb.
Sadly I don't even begin to have the skills to do this myself!