zlacker

>>nullch+(OP)
If you want excellent ligature support I would recommend Fira Mono. There are powerline variants, too. Lately I have been in love with IBM Plex Mono, but no ligature support.

>>whales+Rp1
You can add the Fira ligatures to any font with Ligaturizer. Personally I use it with CMU Typewriter.

[1]: https://github.com/ToxicFrog/Ligaturizer

>>wprl+xE1
I remember that I tried to use it to add ligatures to Fira Sans and it didn't work well.