git branch used to return all local and remote repositories.
Only git branch -a would return all local and remote tracking branches (branches, not "repositories").
Check first if, as commented, this is a pager issue. Change shell (if you are on Windows, switch between CMD, Powershell or bash, to see if the issue persists)
git --no-pager branch does work!
How do I fix git branch based on this info?
As noted in git config:
To disable pagination for all commands, set core.pager or GIT_PAGER to cat.
git config core.pager cat
But for disabling it only for git branch, you have various options as described in the similar question "How do I prevent 'git diff' from using a pager?"
An alias for git -P branch would be one of them. (-P is --no-pager)