I run https://bannerjs.com which is a configurable banner announcement service for websites that currently brings in $220 MRR.

I also run https://www.junior-to-senior.com which is a career advice newsletter for programmers that currently brings in $0 MRR, mainly because I'm focusing on content and growing the audience right now and haven't looked into sponsorships or paid subscriptions yet. I'd like to get it to a point where I can run it as a publication with multiple authors.