A well designed clear font will increase the readability of programming source code.
The fonts listed below are some alternatives to the default monospaced OS fonts (Courier / Courier New, Consolas, Lucida Console, Monaco).
The ideal font will depend on your monitor size and DPI, font size and whether you use Font Smoothing or ClearType.
ClearType and the fonts hinted to use it (Calibri, Consolas), do not display well on tablet devices when rotated 90°.
When programming, you will want to be able to easily distinguish different punctuation, quotes, parenthesis etc.
Sample strings, each of the characters below should look different:
quotes: ' `´ ‘’ " “ ”
|!1lIi
0Oo
,.;:_-=+
Parenthesis: (){}[]
Anonymous Pro by Mark Simonson - Full unicode and bitmap support.
Andale Mono - via Microsoft Core fonts.
Adobe Source Code Pro by Paul D. Hunt, (also the companion Source Serif Pro by Frank Grießhammer).
Bitstream Vera Sans Mono by Jim Lyles. A derivative of Vera Sans Mono, Menlo, was provided with Mac OS X until 2015. DejaVu fonts are also based on Vera.
B612 and B612 mono - a highly legible open source font family designed and tested to be used on aircraft cockpit screens.
Courier Prime - an updated version of Courier with true italics, designed primarily for screenplays.
IBM Plex Mono - Full font family with sans and serif by Mike Abbink and Paul van der Laan.
Droid Sans Mono - via the Google Andriod project.
Fira Code - A Monospaced font with Ligatures. Sponsored by Mozilla, (also the companion Fira Sans).
Ligatures do have some downsides for program code.Hermit - a monospace font where similar characters have been designed to be very distinguishable from each other. Donationware.
JuliaMono - A monospaced font originally designed for programming in the Julia Programming Language and in other text editing environments that require a wide range of specialist and technical Unicode characters.
Inconsolata by Raph Levien, similar to Consolas but works equally well with ClearType on or off.
Monoid by Andreas Larsen, an example of Class Based Contextual Positioning.
Mononoki - a typeface by Matthias Tellen, created to enhance code formatting. Donationware.
Overpass Mono - Gogle fonts, Open Font License, designed by Delve Withrington, Dave Bailey, Thomas Jockin.
Triplicate - serif monospace includes a Code variant with characters optimized for programming and terminal windows.
Ubuntu Font - custom designed font with a very distinctive look and feel.
Input is a flexible system of fonts designed specifically for code by David Jonathan Ross. It offers both monospaced and proportional fonts, all with a large range of widths, weights, and styles for richer code formatting.
Goldman Sans - a sans-serif typeface designed for dense data-rich environments e.g. Excel. Careful attention was given to legibility at small sizes and to distinguish commonly confused shapes, for example 5 & S, I and l. Numbers are by default set to ‘tabular’. This important detail ensures that columns of numbers are always aligned.
“There’s nothing like tight kerning to make a design look dean and modem” ~ Dan Wineman
Related
programmingfonts.org - Samples of many fonts.
Catrinity - Unicode font with support for a large number of Unicode blocks.
Everson mono - Unicode font with support for a large number of Unicode blocks.
Charter - A free body text / screen font designed by Matthew Carter.
Google Noto - Open source unicode font, Noto Sans and Noto Serif support 581 languages.
Cooper Hewitt - A contemporary sans serif, by Chester Jenkins free for unrestricted public use under the SIL Open Font License.
iOS fonts - List of fonts supported in iOS.
Microsoft Core fonts for the Web - via MajorGeeks