[freehunter]

But this has zero explanation. It's more like an appendix than a cheatsheet. It lists all the flexbox commands you can use, but doesn't say a single word about what it is.

flex-direction: row (The flexible items are displayed horizontally, as a row) is a cheatsheet. flex-direction: row is just a command.

[exodust]

I agree, and for simply learning flexbox in 5 minutes (really it's that easy), I used:

https://www.w3schools.com/css/css3_flexbox.asp

the "try it yourself" links are handy.