As a developer, you spend most of your time working with tools that other developers have spent time crafting. You might feel inclined to give back (that's a great thing!) and if that's the case, here are a few resources that might help.
first-contributions
Hands-on tutorial that walks you through contributions workflow on github
Up for grabs
List of issues reported in open source projects that the maintainers have identified as good projects to tackle for a beginner to the project
Publish your own package