More categories in tactics trainer

[XenonOxide]

I'm really enjoying the new-look lichess tactics trainer so far, but I'm noticing that there are a few categories missing that deserve to be there. Two I can think of off the top of my head are "overloading" and "sham sacrifice". I'm sure there are others that I'm forgetting.

[ornicar]

Overloading is included in deflection. What is "Sham sacrifice"?

To add maybe: "backward move", "knight and bishop endgame", "recapture sequence", "master games"