Just compare him to Rampant Growth or Diligent Farmhand
Our options are therefore as follows: Azorius v Jund: Will, Scion of Peace & Ikra Shidiqi, the Usurper + Kediss, Emberclaw Familiar Rakdos v Bant: Judith, Carnage Connoisseur & Shanna, Purifying Blade Selesnya v Grixis: Trelasarra, Moon Dancer & Solkanar the Swamp King Boros v Sultai: Firesong and Sunspeaker & Zimone and Dina Golgari v Jeskai: Beledros Witherbloom & The Archimandrite Okay, there should be six, but if you can find an oppositional pair in Dimir and Naya that can both be reasonably called a life gain deck, go for it
Saheeli, Filigree Master You can +1 her to scry 1 and then tap an artifact you control and draw a card, so scry into card draw is quite nice
The invocations will definitely keep her price down, though, so dont get too many copies
The details can be blurry
(9/25/2020) If a land entering the battlefield at the same time as Ancient Greenwarden (including Ancient Greenwarden itself if an effect causes it to be a land) causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.