As a guitarist I’ve always loved tremolo pedals, which modulate volume rhythmically.
Ableton’s Auto Pan does this perfectly. You just to set Phase to 0 to affect volume instead of panning. This preset does it for you:
Tremolo.adv
You can change the shape of the modulation from a smooth sine wave to a more abrupt square wave, change the phasing (when volume starts to go up or down) or whatever else really when you start racking with other effects. This is my go to rack for tremolo and chorus for guitar and keyboard:
Tremolo + Chorus [jethroe].adg