The Nielsen-Norman Group newsletter on usability, design, and UX research (https://www.nngroup.com/articles...), and the JP Licks monthly newsletter (a Massachusetts-based ice cream shop with a lot of personality!).
Brain Pickings by Maria Popova.
Maria devoted her life to reading and connecting ideas across history and cultures. Her newsletter is guaranteed to make you a better human being: https://www.brainpickings.org/
A little less conventional but I love the one from exec coach Ed Batista - you can subscribe on his website https://www.edbatista.com/. Soulful and spiritual food for thought :)
Graph.one
Orbit
Typogram
Blogging for Devs
Fomo Fix
Product Hunt Launch Checklist
Marble: Insurance Savings & Automations
🍅 juicy timer.
Master Expert
Echelon+
Conjure
Pages by Scribe
HackerPulse
Spiritory