I use a custom font[1] I made ;). I'm still learning bits of typography, so it's not the most legible, but it was fun to make.<p>[1]: <a href="https://ermineii.github.io/befont.html" rel="nofollow">https://ermineii.github.io/befont.html</a>
SF Pro Mono with Powerline symbols. I use it on all my OS actually, not just macOS but Windows and Linux as well. You can download it off GitHub repositories. Probably against Apple's TOS, but well, it's a nice font.
Currently loving Fira Code. Took some time to get used to ligatures, but they actually work pretty nicely. In addition to ligatures there are lot of well thought design details that increase legibility.
<a href="https://github.com/tonsky/FiraCode" rel="nofollow">https://github.com/tonsky/FiraCode</a>
I went with Proggy TT with slashed zeros for a long time. Using a bitmapped font seems less necessary now that I have a 4k monitor, so I've defaulted to Consolas (in Visual Studio Code and also for my terminal sessions), which is nice enough that I haven't been actively looking for a replacement.
I’ve tried a lot, and I still do, but I always come back to Mononoki<p><a href="https://madmalik.github.io/mononoki/" rel="nofollow">https://madmalik.github.io/mononoki/</a>
Liberation Mono. I haven't thought much about this choice. I only really care that similar characters are easily distinguishable, such as '1' and 'l'.