X4 Fortress Boss Sprites
Complete Sheets
Reference Sheets

What's the difference between the two folders?
Depending on what you want to use these sprites for, you may find one or the other more useful.
"Complete Sheets" have every possible pose and more, but since these have been tile ripped, you'll have to put them together yourself.
For the more tricky bosses, and because you may have no idea WHAT goes where, reference sheets have been left up.
Use whichever you find more useful, but the latter have not yet had their palettes corrected.
Since some of the complete sheets are fairly no-brainer to use, not every boss requires a reference sheet.