Flexbox Zombies is described as 'Flexbox is incredibly powerful. But it's also crazy hard to master. So we all end up depending on a cheat sheet and some mad guessing in the dev tools. Enough of that!' and is an website in the Development category. There are seven alternatives to Flexbox Zombies, not only websites but also apps for Self-Hosted solutions. The best alternative is Flexbox Froggy, which is both free and Open Source. Other great sites and apps similar to Flexbox Zombies are Flexbox Defense (Free), Super Markup World (Free, Open Source), Flexbox Patterns (Free, Open Source) and Awesome Flexbox (Free, Open Source).