Basic blender went bad (motor ran but spindle wasn’t rotating). I wanted to disassemble to see if it could be repaired. Three of the four screws were Phillips head. I had to cut the casing open in order to discover why I couldn’t unscrew the fourth. It was a slotted spanner.
The bit set and tool set from IFixIt has those. I’m not sponsored by them in any way, but I will shamelessly recommend their tools when I can because they’re objectively good for this kind of stuff.