Acorn Catapult Acorn Harvest Acornelia, Fashionable Filcher Animal Friend Cache Grab Camellia, the Seedmiser Chatter of the Squirrel Chatterfang, Squirrel General Chatterstorm Chittering Doom Chitterspitter Cloakwood Hermit Comet, Stellar Pup Deep Forest Hermit Deranged Hermit Drey Keeper Druid's Call Earl of Squirrel Form of the Squirrel Hazel of the Rootbloom Honored Dreyleader Liege of the Hollows Mistakes Were Made Mudflat Village Nantuko Shrine Nested Shambler Nut Collector Oakhollow Village Ravenous Squirrel Rootcast Apprenticeship Scurry Oak Snickering Squirrel Specimen Collector Squirrel Dealer Squirrel Farm Squirrel Mob Squirrel Nest Squirrel Sanctuary Squirrel Squatters Squirrel Stack Squirrel Stack Squirrel Stack Squirrel Stack Squirrel Stack Squirrel Stack Squirrel Wrangler Steel Squirrel Swarmyard Swarmyard Massacre Sword of the Squeak The Odd Acorn Gang The Unbeatable Squirrel Girl Thornvault Forager Trendy Circus Pirate Underworld Hermit Valley Mightcaller Vedalken Squirrel-Whacker Verdant Command Wrenn and One (playtest)

and its a good ooze to consider as your only one in a Volo, Guide to Monsters deck
I havent noticed many lifegain decks running around recently, at least not in Standard, but they do exist in abundance in Pioneer and Explorer, so it might be intended for those formats
Its no wonder that Mox Ruby has been a staple in Vintage and an essential piece in Magic the Gatherings competitive history
Released in the very first set of the game, Dark Ritual is a staple in every format it's legal in, from the casual Commander format to the highest-powered formats of Legacy and Vintage