err... no? sorry, but i literally don't understand what you meant. can you clarify?
Any sprite, art or asset that is thrown into the
Spiral Arms (and its
Sequel) can be used, kitbashed or recycled, usually for being free stuff for modders to remake compared to Spriters' Jugdement where the post is used only to criticize someone's work. Most of them are usually a lost cause (minus Helmut's stuff and some other veteran modders), though it's always polite to ask permission first.
Unless the owner wants the throwaway back or have them removed from their posts, though that rarely happens.
Though I think he means, when there's a custom sprite is made in there, it's likely to be (or a part) of the bosses that appear in the
Ship/Weapon Pack's Interstellar Bounty Board. Which has tons of them already, and some also exist in faction mods.
Raptor Interceptor
Jackal Heavy Fighter
These look nice especially from someone who started making new assets.
It has that 16-bit style, though not usually set for 24/32-bit in the game's styling. A bit of shading on their wings and some shine in the cockpit may be enough.