Didn't know these exist, love it: Monospaced Programming Fonts with Ligatures.
Three of the most interesting and thoughtful monospaced programming fonts with ligatures are Fira Code, Monoid, and Hasklig. I say "thoughtful" but that's what I really mean - these folks have designed these fonts with programming in mind, considering spacing, feel, density, pleasantness, glance-ability, and a dozen other things that I'm not clever enough to think of.
Most of these fonts have dozens and dozens of ligature combinations and there is no agreement for "make this a single glyph" or "use ligatures for -> but not ==> so you'll need to try them out with YOUR code and make a decision for yourself. My sample code example can't be complete and how it looks and feels to you on your screen is all that matters. […]
Look at how "www" turned into an interesting glyph. Things like != and ==> turn into arrows. HTML Comments are awesome. Double ampersands join together.
I was especially impressed by the redefined hex "x". See how it's higher up and smaller than var x.