@fredowald and I created a small README-badge service for small projects which need help in maintenance. It is meant to encourage visitors of open source projects to rather complain but help out creators of open source projects.
See it in action: https://github.com/fin-ger/loop-calc
Setup a `looking for maintenance` badge for your project: https://maintenance.rocks/
Server run by the main developers of the project 
It is not focused on any particular niche interest - everyone is welcome as long as you follow our code of conduct!