A box of bits for basing and terrain. Stuff that can be glued down on hills and walls. I'd rather have a wide selection than duplicates, one can always buy another box. Perhaps a mix of eras?
Ideas for the sprue:
Barrel and Crate (half on sprue, combine two sprues).
Weird bones (dog, cow, other animals, mythological creatures, unidentifiable).
Human bones (altough the skeleton warrior set does nicely, really).
Litter (broken bottle, cloth, broken backpack, overturned mug, splintered wood).
Bottles (beer, wine, jug, a glass or two. People like alcohol
Machinery (some cogs and gears, detailed machine parts).
Strips of riveted plate (a couple of different widths).
Squares of metal plate (cross-hatched-pattern, with studs, with holes).
Backpack (perhaps a sack or puch as well).
Details for piping (end pieces, valves. Glue to straws or plastic tubes).
I'm sure there are other good ideas out there
I left out weapons on purpose, as the other kits should come with plenty of extras.. An axe + hobby knife = broken axe
I can get some of these with Hirst Arts, but I don't own the molds, shipping the stuff is expensive, and a WGF box is way neater on the shelf