-1/-1 counters with aristocrat themes. No infect here! (cept that one smol boi but he just cheap value)
Update: Figured I should point out potential combos/synergies both infinite and not.
Easiest Combo:
With only Hapatra, Vizier of Poisons and Blowfly Infestation, you can create an infinite loop that will both kill and create a 1/1 green snake. now all you need is a 3rd piece to generate either ETB value or death trigger value. For infinite life loss/life gain you can use Zulaport Cutthroat, Obelisk Spider, or Blood Artist (not in deck list). To make all of your creatures in play infinitely large you can use Ivy Lane Denizen.
Other Combos using Hapatra and Blowfly Infestation:
If you are struggling to find a combo piece to close out the game, infinitely killing your snakes while having Catacomb Sifter in play will let you scry through your deck and put any crucial card on top of your library. Having Moldervine Reclamation in play while infinitely killing your snakes will let you draw you library and get those crucial combo pieces and game enders into your hand.
Other Infinite/Near Infinite Combos:
Hapatra, Vizier of Poisons and Yawgmoth, Thran Physician have insane synergy. While it is not infinite, you may essentially pay life to place -1/-1 counters and draw cards. Sacrifice a snake to Yawgmoth and pay a life to place a -1/-1 counter and draw card. When you place the counter Hapatra will create a snake, thus giving you a repeatable usage of Yawgmoth. This combo is of course finite due to it being restricted to the amount of life you can pay and due to running out of creatures to place counters on.
There are several cards that can increase the power of this combo. having any of the cards named in the previous combo will empower this one. Having Zulaport Cutthroat will make up for paying life, as well as bleeding your opponents. Moldervine Reclamation and Ivy Lane Denizen will also have the same effect as previously stated.
To turn Hapatra and Yawgmoth into a Necropotence, you will need one of two token generators. Nest of Scarabs or Flourishing Defenses
will provide you with your infinite source of sacrifice cost as well as a target for your -1/-1 counter. This allows you to essentially pay 1 life to draw 1 card.
Lastly, to make this combo near-infinite, you will need a combination of Hapatra, Yawgmoth, either of the 2 token generators, and any of the life loss/life gain creatures(ie Zulaport). This will essentially make all of Yawgmoth's ability's costs free. You will be able to draw a card and make each opponent lose a life. As long as you have more cards in your library than your opponents have life, YOU WIN!
Another infinite combo you can pull of very easily is by using Devoted Druid and either Quillspike or Ivy Lane Denizen.
Devoted Druid and Quillspike will allow you to create an infinitely large Quillspike. While this combo is somewhat common, it can be great for a sneaky attack or surprise block. If you have Rogue's Passage in play you can quickly one-shot a player. Additionally, if you have Hapatra in play, you will also be creating infinite 1/1 snakes. Depending on the board state this could easily be a game ender, but be warned that infinite creature combat phases are much easier to disrupt (i.e. Fog, Propaganda, etc).
Devoted Druid can also generate infinite green mana when paired with Ivy Lane Denizen and Hapatra. Activate Devoted Druid's second ability by placing a -1/-1 counter on her and untapping her. When you place the counter, Hapatra will create a snake. This allows Ivy Lane Denizen to trigger and put a +1/+1 counter on the Devoted Druid. This synergy will allow you tap and untap Devoted Druid infinitely, generating endless green mana and endless snakes. TIP Feel free to toss in a Gemstone Array with this combo to generate infinite mana of any color or any X-cost spell to end the game! I chose not to run Array simply because the artifact is useless outside of this combo.
Additionally, any of the combos that generate infinite snakes can now be a game ender using Hooded Blightfang. Simply declare attacks and all your opponents will die!
All other cards in the deck have top notch synergy with Hapatra, -1/-1 counters, and aristocrats. All other cards should be self explanatory but if you have any questions, leave a comment!