What is the current meta after a 12 month break?

I've had an itch to get back into SC2 after a lengthy break.  I'm currently playing some "get back into it" games and will subjectively adapt, but I would love to hear what the current state of the game is!

As of a year ago, I was a diamond level Zerg player.

What are the most zerg effective maps, builds, concepts, and issues to be aware of given the numerous updates that I've missed out on?