Git Config Settings I Always Recommend

If you've ever worked on a project with me then I've probably recommended at least one of these config settings in git.

git config --global pull.rebase true - tells git to always pull with rebase instead of merge (the equivalent of pull --rebase). This not only saves you having to type the flag every time, but also ensures gui clients will also use rebase when pulling. Note: You should only enable this if you’re comfortable with rebasing.
git config --global fetch.prune true - tells git to automatically run git remote prune after a fetch. This will clean up any local objects that no longer exist on the remote like tracking branches that have been deleted from the remote server.
git config --global rebase.autoStash true - tells git to automatically stash when you perform a pull and then attempt to unstash them once the rebase is complete. This is almost always my workflow so it's nice to have git do it for me.
git config --global rebase.autosquash true - tells git to automatically include the --autosquash parameter when doing a git rebase --interactive. You should read more about autosquashing commits if you're unfamiliar with it. I use it all the time for fixing up or rewording previous commits.

Newer settings

If you haven't updated git in a couple years then you should as it's worth it just for these new config options.

git config --global push.useForceIfIncludes true (2.30.0) - This setting makes push --force-with-lease even safer. See the docs for more info.
git config --global push.autoSetupRemote true (2.37.0) - Git will automatically setup an upsteam tracking when you run git push from a new branch.
git config --global rebase.updateRefs true (2.38.0) - the --update-refs option makes working with stacked branches easier

You might find these useful depending on your personal workflow.

git config --global commit.verbose true - Git will include the diff of the changes at the bottom of the commit message template. I like this because your text editor can then autocomplete variable or function names you want to include in the commit message.
git config --global rerere.enabled true - It stands for Reuse Recorded Resolution, and tells Git to remember how you resolved a merge conflict and automatically reapply if it sees it again.