Coding Fonts is a fabulous resource from CSS Tricks for selecting alternative fonts for your code editor.
While a few of the fonts are commercial, many are open source and/or free.
In Sublime Text 3, changing the font is as simple as downloading and installing the font then opening Preferences > Settings then adding the following line of code to the right-hand pane (within the file ‘Preferences.sublime-settings — User’):
"font_face": "NAME_OF_FONT",Save the file and the font updates instantly.