Stuff good enough to vouch for. For food, see the leaderboards.
Postgres with auth, storage, and row-level security out of the box. Powers this entire site on the free tier.
The maps on this site. Great docs, a generous free tier, and full control over markers and popups without fighting an iframe.
Zero-config private network between your devices. Install it, log in, and everything can reach everything — securely, from anywhere.
Notes as plain Markdown files you actually own. Fast, local-first, and it will still work in twenty years.