My current work uses Gitlab for source control and compared to Github the interface is quite a lot more basic. I've had a Sublime Merge license for ages as I generally use Sublime Text as my editor outside of work but I'm really heavily leaning on its functionality now.
Initially it was just to be able to access the history and blame views that I'm used to but I've also started to use it to manage staging files and to correct mistakes in local commits. Historically I've probably used the command-line for this but once you're in a GUI tool then it is often easier to stay within it.