Spacebar lets you preview lots of different kinds of files in the macOS Finder, like .sqlite3 and .geojson
It also lets developers write plugins to support more kinds of files - just by writing html and javascript!
brew tap gregsadetsky/tap && brew install --cask spacebar
Note: the app is not currently signed with an Apple developer id (I'll do it after I get 10ish stars on GitHub!).
For now, either go to System Settings → Privacy & Security → (find the app at the bottom of the window, then click) Open Anyway
... or, run
xattr -dr com.apple.quarantine ~/Applications/Spacebar.app
If previews don't show, go to: System Settings → General → Login Items & Extensions → Quick Look and make sure that Spacebar is enabled