Orochi Sustainer

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Sachi, Daughter of Seshiro

Other Snake creatures you control get +0/+1.
Shamans you control have "{T}: Add {G}{G}."

Tangled Islet

({T}: Add {G} or {U}.)
Tangled Islet enters tapped.

Witty Roastmaster

Alliance — Whenever another creature you control enters, Witty Roastmaster deals 1 damage to each opponent.

Xyris, the Writhing Storm

Flying
Whenever an opponent draws a card except the first one they draw in each of their draw steps, create a 1/1 green Snake creature token.
Whenever Xyris, the Writhing Storm deals combat damage to a player, you and that player each draw that many cards.

Mold Adder

Whenever an opponent casts a blue or black spell, you may put a +1/+1 counter on Mold Adder.

Wooded Ridgeline

({T}: Add {R} or {G}.)
Wooded Ridgeline enters tapped.

Sosuke, Son of Seshiro

Other Snake creatures you control get +1/+0.
Whenever a Warrior you control deals combat damage to a creature, destroy that creature at end of combat.

Coiling Oracle

When Coiling Oracle enters, reveal the top card of your library. If it's a land card, put it onto the battlefield. Otherwise, put that card into your hand.

Molten Tributary

({T}: Add {U} or {R}.)
Molten Tributary enters tapped.

Kashi-Tribe Elite

Legendary Snakes you control have shroud. (They can't be the targets of spells or abilities.)
Whenever Kashi-Tribe Elite deals combat damage to a creature, tap that creature and it doesn't untap during its controller's next untap step.