I use Triplicate, Concourse and Equity extensively. Equity, there are surprisingly few fonts like it in its organic feel and faithfulness to the old art of printing. (This doesn’t convey as much as I’d like, but I lack the terms of art to describe what I mean properly.) Triplicate, well, it’s the only good true serif monospace that I know of, and I like that. Each font fills a niche that I very much appreciate. I reckon they were worth buying on their own merits, but it was also then a way of supporting Matthew Butterick’s project https://practicaltypography.com/ which I strongly approve of as a project.