Humbug Uldra

This is the main deck I've been playing since Uldra arrived. I'm not sure exactly how good it is, but I think it is competitive and it has some extremely good matchups (and some bad ones).

The deck looks a lot like reanimator with the Uldra package in place of Vara/Azindel/BSH/Grasping, but it actually plays out a decent amount differently. Here are some points of comparison:

1) Going off with Uldra isn't as good as fully going off with Vara + Azindel + BSH in most ways (you don't get to BSH their board a couple times, steal several cards from their deck, and Sabotage them once or twice...). With Uldra, it helps a lot if your opponent's life total is somewhat low so that you can just burn them out with Quake Titans (and/or create a wide enough board with Vishnis to kill them on the following turn).

2) But with this deck, you do get to do stupid things much earlier than turn 5, and without much setup. Remembrancing a Vishni on turn 2 or 3 is the dream and happens reasonably often, but Remembrancing a Quake Titan that early is also great at pressuring the opponent's life total. Having strong proactive plays early in the game is nice and helps your Uldra later on actually just be lethal.

3) Reanimator plays Back-Alley Delinquent in large part because it needs answers to Harsh Rule. This deck just doesn't care about Harsh Rule at all. Harsh Ruling an Uldra usually just causes the opponent to die immediately, and even if they can kill Uldra before the Harsh Rule, your units aren't Voidbound or anything so you can just play a second Uldra. Not caring about Harsh Rule is nice since it means that you get to play better discard outlets than Delinquent - the Spitefeeder/Gustrider "Humbug package" (Spitefeeder is a good way to onslaught Gustrider) is good both at dumping shift units into your void and at pressuring your opponent's life total a little bit so that you can burn them out.

4) This deck is actually more consistent than reanimator in some ways because Remembrance can act as extra copies of Merchant, Gustrider, or Sporefolk in a pinch. Remembrancing Vishni/Titan is still the most common and most powerful thing to do, but don't hesitate to do other things with the card too.

I don't know whether this deck is better or worse than reanimator, but for the reasons above it plays out quite differently - you do busted things earlier and more consistently and you don't have to worry about annoying things like merchant -> sweeper, but you actually have to do lethal damage instead of just dominating the game with Azindel and BSH.