PaceBar

PaceBar is best for solo Mac users or freelancers who want a private, no-fuss way to gauge how draining their workday is.

You get a real-time session load score with zero data leaving your device, which is a genuine strength for privacy-conscious workers. That said, there's no public pricing, no team features, and it's a very early-stage tool — so hold off if you need something proven or need to share insights with a team.