Hai. New here. I thought my deck could use some refining before I took it to a tourney, and I wanted some feedback. As per the title, I'm building this deck primarily for fun, but if I can win that's a plus.

Aurochs are easily one of the most undersupported creature types in all of Magic, with just 4 creatures: Aurochs, Aurochs Herd, Bull Aurochs, and Rimehorn Aurochs. But Changeling is a thing. So Aurochs Herd can search any Aurochs, a.k.a. any Changeling.

Now for decklist:

Forest x9
Plains x8
Island x7

Aurochs x2
Aurochs Herd x2
Bull Aurochs x4

Ameboid Changeling x1
Avian Changeling x1
Changeling Titan x2
Mirror Entity x1
Shapesharer x3
Shields of Velis Vel x1
Wings of Velis Vel x1

Shared Triumph x2
Obelisk of Urd x3
Adaptive Automaton x3
Door of Destinies x3
Crown of Vigor x1
Coat of Arms x1
Alpha Status x1
Stoneforge Masterwork x1
Urza's Incubator x3

Some of you may be thinking, "But isn't this mostly modern?" Not all of it is. I couldn't find enough good support in modern, so I went vintage. Besides, Aurochs is a vintage card anyways.

@AurochsNewMeta Aurochs are extinct... Ok that's mean. Please please please win a vintage match with this thing. Hook em' horns!

Are you aware that there's a mono green pauper deck that runs 4x Aurochs Herd?

I'm not sure why you're running all the shapeshifters. Do you need a minimum number of Aurochs for tribal reasons?

Also it's not a very budget friendly card these days, but your deck could benefit from some number of Cavern of Souls.

I also dug this up for you. It apparently loses to myr, but myr are awesome, so that's to be expected...

@Gumgod No, I didn't know that. That's interesting.

I'm using all the shapeshifters to get the maximum bonus off the Aurochs ability.

@AurochsNewMeta Mutavault?

I think if you really want to embrace vintage with this deck you really need to add a sol ring at least.

Mutavault is a good card though.

For the record it's a really good pauper deck. If you are interested in being highly competitive I'd suggest that format.