If you want to know the latest branches that you did workon in git, you can use this simple command

git reflog | grep 'checkout: moving' | awk -F ' to ' '{print $2}' | awk 'seen[0]++' | head -n 20

In detail:

• git reflog gives you your git history
• grep 'checkout: moving' to filter only on latest "moving" operations. Will give you something like 6f6071873 HEAD@{1}: checkout: moving from branchname-a to branchname-b
• awk -F ' to ' '{print $2}' keeps only the branchname of the line (branchname-b)
• awk 'seen[0]++' to remove duplicates
• head -n 20 to keep only 20 latest lines

You can make it a git alias in your gitconfig file (watch out for the backslashes):

[alias]
    latest-branches = "!bash -c \"git reflog | grep 'checkout: moving' | awk -F ' to ' '{print \\$2}' | awk '!seen[\\$0]++' | head -n 20\""