Here's a card I'm surprised hasn't had a thread yet:
Scuttling Doom Engine 6
Artifact Creature - Construct
~ can't be blocked by creatures with power 2 or less.
When ~ dies, it deals 6 damage to target opponent.
6/6
So it has a solid body, and some relevant abilities. The first question is obviously what would make you want to play it over a Wurmcoil Engine. The first answer to that would be that it's a better aggressive creature since most things in Vintage can't block it, meaning that it's more likely to connect than Wurmcoil, and while gaining life can be pretty big it still leaves you dead if they combo off with Vault, and thus the ability to put out damage can be better while also dodging things like Strix or Ophiomancer tokens. The second answer would be that there are times when this has a better dying trigger than Wurmcoil. Sacrificing a Wurmcoil while facing down a TNN isn't going to do much since they can just block the tokens, while sacrificing this can easily end the game since it does a fair amount of damage. Additionally, this is better in the case that they have something like Energy Flux or something along the lines of Chewer + EE.
I'd still say that Wurmcoil is the better overall creature, but if you're going for something like Cat Shops, this guy can easily be a strong contender since he's a pretty solid aggressive creature that can do some fun things with cards like Welder or even Forgemaster. Cloning him with Metamorph or Image is also just rather brutal since you're pretty much instantly dead if it connects once at that point and your removal kills it instead of bouncing it or exiling it, unlike Wurmcoil which gives you an extra turn usually.