• https://medium.com/@kentcdodds/first-timers-only-78281ea47455#.4zdpfigcb
• https://opensource.guide/how-to-contribute/

Platforms

• https://openhatch.org/
• https://www.codetriage.com/
• http://up-for-grabs.net/#/

Social media

• https://twitter.com/yourfirstpr

Github tags

Unfortunately, Github's search doesn't support OR operator over labels (or at least I don't know how), so here a list ordered by number of open issues at the moment of writing:

• easy
• beginner
• [Good First Bug](https://github.com/search?utf8=✓&type=Issues&q=state%3Aopen+label%3A"Good First Bug")
• starter
• E-easy
• newbie
• [easy fix](https://github.com/search?utf8=✓&type=Issues&q=state%3Aopen+label%3A"easy fix")
• easy-fix
• [beginner friendly](https://github.com/search?utf8=✓&type=Issues&q=state%3Aopen+label%3A"beginner friendly")
• easy-pick
• [Good for New Contributors](https://github.com/search?utf8=✓&type=Issues&q=state%3Aopen+label%3A"Good for New Contributors")
• first-timers-only
• contribution-starter
• [good for beginner](https://github.com/search?utf8=✓&type=Issues&q=state%3Aopen+label%3A"good for beginner")
• [starter bug](https://github.com/search?utf8=✓&type=Issues&q=state%3Aopen+label%3A"starter bug")
• good-for-beginner
• your-first-pr
• [first timers only](https://github.com/search?utf8=✓&type=Issues&q=state%3Aopen+label%3A"first time only")
• [first time contributor](https://github.com/search?utf8=✓&type=Issues&q=state%3Aopen+label%3A"first time contributor")

If I missed some relevant tag, put it in a comment and mention me to add it.

Other compilations

• https://github.com/MunGell/awesome-for-beginners

Some specific projects

• https://webcompat.com/
• https://wiki.mozilla.org/Mobile/Get_Involved#Mentor_Bugs
• https://github.com/sindresorhus/module-requests/issues