u/Haamflaagon

Toph, Hardheaded Teacher + Sanctum of Ugin in play. Herigast, Erupting Nullkite in hand. 

1. Cast Herigast. When you cast Herigast, both Toph and Sanctum will trigger. Resolve Toph first to earthbend Sanctum. Sanctum will then sac itself to fetch Bygone Colossus. The earthbend trigger will then return sanctum to play, meaning this interaction can be repeated when you cast any of the following combo pieces to find the next combo piece. 
2. Cast Bygone Colossus for its warp cost - fetching Skittering Battalion. 
3. Cast Skittering Battalion using its emerge cost granted to it by Herigast, sacking Bygone Colossus - fetching Ulamog, the Infinite Gyre. 
4. Emerge Ulamog by sacking Battalion - fetching Su-Chi Cave Guard. 
5. Emerge Cave Guard by sacking Ulamog - Resolve ulamog’s triggered ability before fetching Skittering Battalion with sanctum. 
6. You will now be able to repeatedly cast these 4 cards to destroy all opposing permanents and create an infinite army of hasty 4/4’s.

 

You need a total of 6 mana after casting Herigast to perform the combo. This can be reduced to 3 if your deck has at least 1 more colorless 7 mana creature. You need to play the cards in a slightly different order though.

Grist, the Hunger Tide + Sac outlet in play. Doomsday in hand. 

• Nantuko Tracer (Top)
• Primordial Gnawer
• Hornet Queen
• Dread Return
• Living End (Bottom)

1. Sac all your creatures. 
2. Resolve the death trigger of Primordial Gnawer - casting Living End from the top of your deck - returning all creatures in your graveyard to the battlefield. 
3. The etb triggers of both Nantuko Tracer + Hornet Queen will go on the stack. Resolve Nantuko Tracer’s first to put Living End back into your library. 
4. Before letting the etb of Hornet queen resolve, sac all your creatures. 
5. Let the etb’s resolve to create an infinite army of insects. 
6.  Pass and hope no one has a board wipe.

 

There are also 3 alternatives if you want to win on the combo turn. 

1. Replace Hornet Queen with The Wise Mothman if you have access to blue. 
2. Altar of Dementia as your sac outlet. 
3. You need anything that can use your infinite etb/death triggers already in play or in your hand.

 

You do not need Hornet Queen in scenarios 2 and 3. Consider replacing it with any of the following:

• Ant-Man’s Army gives you infinite treasures to cast your win-con from hand. 
• Carrion Locust can exile pesky creatures from opposing graveyards that would disrupt your loop.

Edit: As a very smart Redditor pointed out, replacing hornet queen with Aatchik, Emerald Radian lets you drain the table without any additional pieces.

1. Sac AIM to Pyre - putting Spellseeker into play - fetching Unearth from library. 
2. During your next turn, cast unearth returning AIM to play. 
3. Sac Spellseeker to Pyre - double the ability with AIM - put Starfield Vocalist + Archaeomancer into play - returning Unearth to hand. 
4. Cast Unearth returning Spellseeker to play - fetching Culling the Weak + Exhume. 
5. Cast Culling the Weak sacking Archaemancer. 
6. Cast Exhume returning Archaemancer to play - returning Culling the Weak + Exhume to hand. 
7. Repeat steps 5 and 6 for infinite black mana. 
8. Cast Culling the Weak sacking Spellseeker. 
9. Cast Exhume returning Spellseeker to play - fetching Exsanguinate. 
10.  Cast Exsanguinate using your infinite black mana to drain the table.

Also, is this the sub for this type of post or is there another subreddit you would recommend?