create CSS Grid & Flexbox layout components css / design / dev / generator / resources 06/16/21 CSS Layout Generator[dstelow & stungeye]
play a game, learn about flexbox css / design / dev / games / learning 09/04/20 Flexbox Defense [1rick] (more flexbox resources)
another flexbox-based system css / design / dev / tools 03/02/16 Pintsize — โa simple and modern customisable grid systemโ
flexbox rules in action css / design / dev / resources 12/24/15 display: flex (Test CSS Flexbox Rules Live)