Buildkite (https://buildkite.com/) is so underrated and really nice! Much simpler interface than most other providers like Circle CI or TeamCity and works really well.
Buildkite is my go-to CI in my professional work as well. The hybrid model (the master is SaaS, but you bring your own agents) works so well both from a cost-efficiency perspective, and also when working with enterprises who don't like builds occurring on machines they don't control.
Thanks, this looks interesting, since it lets me build on my own machines (I really need to control the environment, eg. build and test on specific versions of macOS)