USR strikes a great balance between being fast and still being comprehensive. It has one straightforward action resolution system (and it actually uses more than a d20 or a d6!), and it only takes a few moments to create a character. At the same time, the character is more than a handful of numbers. You can actually define a character’s strengths, weaknesses, and background with the choices you make.
USR (Domino Writing style): Includes a character sheet, superhero rules and a full system in just two pages.
USR Wednesdays was the name of my blog until about 2018, where I regularly offered new rules and game ideas for USR. This link goes to an unedited collection of all my posts.
There’s a MeWe page for USR also.