Preshifted sprite
Storing a sprite as several ready-shifted copies, one for each pixel offset within a byte, so the drawing routine never has to shift bits itself.
When several pixels share a byte, eight per byte on the ZX Spectrum or sixteen per word on the Atari ST, a sprite rarely lines up with a byte boundary. Put it at pixel 3 and every row has to be shifted three places and spill into the next byte. On a Z80 or a 68000 those shifts were the most expensive part of the whole routine.
The fix is to do the work once at startup and keep the results: eight copies of the sprite, each nudged one pixel further along. Drawing becomes a straight copy. It costs eight times the memory, which is why plenty of Spectrum games moved their characters two pixels at a time: half the copies, and almost nobody noticed.