Not an exhaustive list:
The Conscience of the King
had a kill setting, and also overload.
Stun seems to have at least two levels: a mild slap-in-the-face stun as seen in The Man Trap,
and then the knockout stuns seen elsewhere.
Scotty used a phaser to cut through a bulkhead in The Naked Time
; "blowtorch" could be its own different setting. Under the original effects, there was no beam shown at all in that case (as if it was --say-- infrared).
Besides settings per se, there are other differences in the beams used in TOS, such as between type I and II power as stated in The Devil in the Dark,
and whether multiple beams are emitted as shown in The Enemy Within.
Also, ordinarily, stun was a different sort of strike on the target from other settings. Frankly, there was a lot of variation in the different kinds of beams emitted.
Also, the original effects on Wink of an Eye
showed a diffuse phaser sweep effect which saturated a corridor, to Kirk's command to "sweep the area" with a stun setting, in contrast to the remastered effects which are more beam like, as shown here