13 GitHub Repos to make your first contribution (JavaScript):

1.altair (label:good-first-issue)
2.Ancient Beast (label: easy)
3.appsmith (label: good-first-issue)
4.AVA (label: good-for-beginner)
5.Babel (label: good-first-issue)
6.Binari (label: up-for-grabs)
7.Botpress (label: contributor-friendly)
8.Brave Browser (label: good-first-issue)
9.cdnjs (label: good-first-issue)
10.Check It Out (label: good-first-issue)
11.Create React App (label: good-first-issue)
12.cypress (label: good first issue)
13.electron (label: good-first-issue)