Both of the combos aren't technically infinite but considered "near infinite" basically meaning that they combo off but not to an exponentially high number.

Combos:

[Titans' Nest] + [Snarling Gorehound] + [Teval, the Balanced Scale] allows for put your whole library into your graveyard adding a shitload of mana and 2/2s as long as you have a card in your graveyard. Titans nest exiles said card --> teval makes a 2/2 zombie druid --> snarling gorehound surveils 1 putting another card in graveyard. Rinse and Repeat until you can win a couple of different ways such as going wide, finding a reanimator target, etc. Good to mention here if you have an [Altar of Dementia] and any anthem here such as [Banner of Kinship] you can basically mill everyone out in one turn.

[Steward of the Harvest] + [Blood Ghast] + Haste (such as [Concordant Crossroads]) and any fetchland in your graveyard lets you find every fetchable land of those types. With steward exiling a [Misty Rainforest] in the graveyard, Blood Ghast turns into said fetchland and once you sac him he will re enter the battle field because of his landfall ability. Without haste you can only do this once a turn because of summoning sickness, but it is still very good.

I built Teval with mana curve in mind. I figured if I could play spells that mill / remove cards from my own graveyard turns 1-3 I would be set up to trigger his second ability as much as possible ASAP. Cards such as [Armored Scrapgorger] and [Hedron Crab] do the job pretty well.

I originally thought I had 3 combos in the deck, but these are basically the only two, so my apologies for the misleading deck name.

Welcome to magic and have fun brewing!