Using up extras from boxes

Almost every kill team box has extras that are used to make the remainder of a team. Most may think to just buy another box and fill teams out that way, but i'm alright with printing bodies and having uneven model counts after i use up a whole sprue. Most recently ive been feeling this towards the spectre squad, but also the kasrkin and goremonger kits.

Does the community know of makers which have models compatible with 40k kits?