This is Olivier from SketchTalk. I have to admit, I'm not a big Sketch plugin user. Currently, it's just Anima's stacking feature that we're all super happy about here at work. So for me it's Launchpad by Anima. Okay, plus this one here maybe: Symbol Instance Renamer to keep my layer list clean.
How about you? What plugins are you currently using? Maybe one you discovered recently?
Here's some plugin inspiration: The Sketch App Hub