Zombicide was a total blast, damn. Way more fun than I thought it'd be.
What expansions/sets should I get? Do the different releases work together?
Well now you're going to learn the downside of being a fan and lttp for virtually every CMON game. Your options are going to be somewhat limited compared to the people who Kickstarted their various games due to all the
really good stuff that will forever remain exclusive to Kickstarters.
Every single thing in every game is backwards and forwards compatible. The best part of this version of Zombicide is the different powers/abilities of the wide variety of unique Abominations and Necromancers, so I would concentrate on getting as many of those as you can as well as different mob types in the main deck.
This is a good place to start your searching:
https://www.boardgamegeek.com/boardgame/176189/zombicide-black-plague/expansions
From what is available:
Base game is a given.
Green Horde is new and introduces harder hitting zombies, 6 new heroes, 10 new missions, the trebuchet, and game tile effects (like water, ledges, and hedges).
Wulfsburg introduces wolves (moves 3 squares per activation), a werewolf abomination, 4 new heroes, and 10 new missions. - man, this may be out of print right now, prices are insane. Don't pay them it will get a reprint
NPC Box 1 - Adds NPCs and some vault weapon cards. I just like the variety and whimsy they add to the table once painted.
Things I would love to recommend, but they are oop right now and resellers are price gouging:
Bosses Abomination Pack - Adds 3 unique Abominations
Crowz enemy box - Adds the crowz enemy
Deadeye Walkers - Adds skeletal archers that can shoot you at range. These can be super rough to deal with.
Rat King - Special Rat summoning Necro and a Swamp Abomination that appears in swamp tiles from Green Horde.
Fatty burster - They blow up when you kill'em! Can be used strategically to blow up a tile full of zombies if you're smart.
The Green Horde Kickstarter has a plethora of everything that makes the game better. Tons of abominations, heroes, and necromancers. You can find people selling this on ebay both together and separated out. Check out this link to see all that was included:
https://www.kickstarter.com/project...ef=nav_search&result=project&term=green horde
The Knight's Pledge Kickstarter from the original BP Kickstarter - A few unique heroes and abominations.
NPC Box 2 - more of the same from Box 1, but with new sculpts and more vault weapons
Nice to have, but not needed:
The various guest artist boxes for additional heroes. Naiade Box should be top of the list because it contains a hero that can also be used as a Necromancer enemy. Many of these boxes are gone forever.
Coming Soon:
Friends & Foes expansion has 6 new heroes, 10 new missions, animal companions, and a new zombie/abomination type
No Rest For The Wicked is an enemy only expansion. It includes the new Spectral Walkers, a HUGE zombie Dragon, rat swarms, and the ballista weapon (similar in concept to trebuchet mentioned above).
Special Guest Boxes Pau Bonner 2, Adrian Smith 2, and Sean A Murray are all great. Between them all you get new heroes, abominations, and necromancers.