I am not talking about SaaS side projects, more exchanging time for money kind of thing. Or anything that just makes money straight away without weeks of upfront 'investment':
Here are mine:
Got invited to trial out some software for Microsoft, got a gift voucher $150.
Did some mentoring on mentorcruise.com, about $160 in total. Stopped as I didn't want to spend the time anymore, so stopped taking on new mentors then let the current ones leave once they were done.
Did some mentoring/coding on codementor.io, about $300 in total. Stopped as I didn't want to spend the time anymore.
I use some of the tools I bought for making my clocks. It makes me feel good to be able help a few small businesses.