Changes:
See the Truth -> replace Tatyova
Teferi, Master of Time -> replace ?
Isochron Scepter -> replace ?
Dramatic Reversal -> replace ?
Mana Vault -> replace ?
Blue Sun's Zenith -> replace ?
Force of Will -> replace ?
Counterspell -> replace ?
Noxious Revival -> replace ?
Muddle the Mixture -> replace ?

Consider:
Switch out some Forests for Islands?
Another sweeper?
** Wild Growth
** Rhystic Study - Great card draw
** Veil of Summer - It's Veil...
* Thought Scour - Card advantage with Rashmi and fuels the yard
* Walking Ballista - Wincon with infinite mana from IsoRev
* Pull from Tomorrow - Mana sink, refueling and scalable cost instant for when I know my top
* Suspend - "Removal"
* Baral - Loot away stuff I don't need and enable more spells per turn cycle
* Roiling Regrowth
Sublime Epiphany
* Reclaim - Trigger Rashmi for cheap at instant speed, and set up the next trigger or draw
Flood of Tears
* Scroll Rack - Put the stuff I want on top
Farseek - Cheap ramp
Simic Signet
* Thought Vessel - Mana rock with no max hand size
* Arcane Denial - Cheap counter
Ponder - Topdeck manipulation for cheap
Gretchen Titchwillow - Mana sink, card draw and ramp
Jin-Gitaxias, Core Augur
God-Eternal Kefnet
Brazen Borrower
Courser of Kruphix - See the top of my deck, and gain some life
* Oko, Thief of Crowns
Brineborn Cutthroat - A cheap flashy threat that can quickly become game-ending, but needs trample or evasion
Ice-Fang Coatl - Cantripping, flashy flier that can have deathtouch if I use snow basics
Winged Coatl - Flashy, deathtouchy flier for relatively cheap
Gadwick, the Wizened - Card draw that can remove blockers or tap scary attackers
Thought Scour - Cheap cantrip that can get rid of stuff I no longer need from the top
Talisman of Curiosity
Riverwise Augur - Brainstorm #3
Unravel the Aether
Regenesis
Starlit Mantle, Eel Umbra - Protection
Uro
Kenrith's Transformation
Preordain - Decent to smooth draws or to set up a good Rashmi trigger
Whispersilk Cloak - Protection for Rashmi or smuggle through an enormous Wildborn Preserver
Opt, Impulse - Instant speed cantrips
Quicken
Run Away Together
Into the Story
Faerie Vandal
Maraleaf Pixie
Vorinclex, Voice of Hunger
Grow from the Ashes, Skyshroud Claim - More ramp that puts the lands in untapped
Temporal Trespass - Delve spell that gets me an additional turn to get value
Rite of Replication - Mana sink and value
Commit // Memory - Protection from mill
Nissa's Pilgrimage
Neurok Stealthsuit
Guardian Project
Aetherspouts
Reason // Believe - Card selection and possible cheating of mana cost
Wood Elves
Nature's Claim
Broken Bond
Bounding Krasis
Boon Satyr
Breaching Hippocamp
Void Grafter - Protection from targeted removal
Horizon Chimera - Flashy dude with some incidental lifegain
Voidmage Husher - Repeatable ability counter or Rashmi trigger
Illusory Ambusher - Card draw/surprise blocker
Harbinger of the Tides - Bounce a dude
Elder Deep-Fiend
Merfolk Trickster
Portal Mage - Redirect a scary creature
Marwyn the Nurturer - I have a surprising amount of elves, but I'd want even more if I add this
Nimble Obstructionist
Torrential Gearhulk
Temporal Mastery - Good with library manipulation
Plasm Capture - Previously cut to cut down counters. Now used in Niv
Scavenging Ooze
Bane of Progress
Nissa, Vastwood Seer
Dictate of Kruphix, Mizzium Meddler, Spirit of the Hunt, Snapcaster Mage, Dimensional Infiltrator, Dictate of Karametra - Flash
Yisan, the Wanderer Bard
Woodfall Primus - Mostly good when it can be recurred and/or sacced, otherwise probably not worth the 8 mana
Archaeomancer
Animist's Awakening
Den Protector
Kiora's Follower

Consider (don't have):
$$$$$ Finale of Devastation - Can fetch any creature at X>9 to make a board lethal. Fetch out Eternal Witness to do it two turns in a row. Scalable cost fits theme
$ Sublime Epiphany - Very flexible counter that can even be looped with an EWit on board
Resculpt
See the Truth
Draining Whelk
Voracious Greatshark - Counter spell on a big guy
Thought Sponge - Card draw
Roiling Regrowth - Second Harrow
Crafty Cutpurse - Good against token decks and things like Dockside Extortionist
Sea-Dasher Octopus
Parcelbeast
Dream Eater - Flashy flier with a bit of size, card selection and tempo
Great Oak Guardian - Surprise blockers or overrun
Cloudthresher - Sweep small fliers at instant speed
* Telling Time
As Foretold
Voidslime
Sakashima's Protege
Plaxmanta - Protection from targeted removal
Glademuse
Naru Meha, Master Wizard
Flood of Tears
Talisman of Curosity
Oversimplify
Dress Down - Stop a combo turn
$$$ Endurance
Guile

Need more copies:
Evacuation - Instant speed sweeper
Reality Shift - Decent blue removal

Potential finishers:
$$$$$ Finale of Devastation - Can finish with any creature if I have a decent board and enough mana
End-Raze Forerunners, Pathbreaker Ibex - Help my dorky dudes be scary
Managorger Hydra - +1/+1 counters and generic green goodstuff
Nightpack Ambusher
Thunderfoot Baloth
Biomass Mutation
Blue Sun's Zenith - I don't have infinite mana, but could have a lot of mana. If not used to mill someone out, I can just draw big
Dramatic Scepter combo if I have some mana rocks to get infinite mana for a Blue Sun's Zenith
Talrand - Utilize counterspells and cantrips to get threats
Champion of Lambholt

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Considered cuts:
Elves, Cultivate/Kodama's Reach - Too much ramp?
Mystical Tutor
Mystic Confluence - How many counterspells should I actually play?
Reclamation Sage, Acidic Slime - Replace with Unravel the Aether or other instant speed removal?
Lightning Greaves - Might not have enough copies
Seasons Past, Eternal Witness
Zendikar Resurgent - I don't have that many creatures, so this is only to make sure I have mana to cast things on each turn
Deadeye Navigator - Mostly used for broken things, but it's a good manasink when I have extra untaps
Coiling Oracle - Nice to get extra lands if I know what's on top, but might not have enough impact
Progenitor Mimic - Simic goodstuff, but otherwise not very synergistic
Sol Ring - Might not have enough copies, so play them in decks without turn 1 mana dorks
Tatyova, Benthic Druid - No real synergy, just a goodstuff card. I probably have enough card advantage with Rashmi that I don't need this
Shared Summons - Do I need this tutor?
Nissa, Steward of Elements - Might be hard to defend
Arixmethes - 12/12 non-evasive might not be good enough?
Mystic Snake/Frilled Mystic - These are very expensive for counterspells, but I do need some bodies, and being blinkable with Deadeye is great

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Cut lands:
Novijen, Heart of Progress
Slippery Karst
Thornwood Falls - Slow, and 1 life isn't much
Lumbering Falls - Slow, and I can't really do much with a 3/3
Emergence Zone - Sacrificing a land to get flash for one turn is a steep cost
Winding Canyons - Most of my important creatures already have flash, and tapping 3 lands to only grant creatures flash is a bit much
Tranquil Thicket, Lonely Sandbar - Cycle extra lands, but they are slow

Cuts:
Simic Signet - Better used in Muldrotha
Pearl Lake Ancient - Has flash, but doesn't really synergize otherwise
Vile Redeemer - I never want to cast it except after a boardwipe, and even then the 1/1s aren't great. They could help get back a decent boardstate, though, but I prooobably won't have enough of them for them to really matter
Pir+Toothy - I don't do a lot of counters, and most of my card advantage isn't draw based
Jace - Hard to protect, and quickly gets hate
Chaos Wand - Expensive to use
Skullwinder - Don't want to give away cards, so it's been upgraded to a larger version in Greenwarden
Burgeoning - No synergy except making use of my draws from Rashmi or Tatyova on opposing turns
Temple of the False God
Bounty of the Luxa - Can't manipulate what I get
Unexpected Results - Too slow and unreliable, and no way to manipulate it
Trygon Predator - Only synergizes with Momir, and is otherwise very boring
Caller of the Claw - Can be decent after a board wipe, but I'm not likely to have enough creatures for this to matter
? Arachnogenesis - Only playable defensively, and only good if their board state is already critical
Greenwarden of Murasa - Expensive, and I have to exile it to get the second regrowth
Rishkar's Expertise - I don't have a lot of big creatures
Ancient Stone Idol - Even with a discount this is likely to be expensive
Explosive Vegetation - Replaced with Risen Reef
Prime Speaker Zegana - Mostly going to be a 3/3 draw 3 for 6, with limited synergy
Lifecrafter's Bestiary - Scry 1 isn't going to help much with the Rashmi-stuff, and I'm not going to be casting lots of cheap creatures to benefit from the drawing
Pondering Mage - Very expensive Ponder with an unimpressive body
? Vivien, Champion of the Wilds - Most of my interesting creatures already have flash
Yeva, Nature's Herald - I have almost no impactful green creatures that don't already have flash
Tamiyo, Collector of Tales - So if I know what's on top, I can guarantee a draw with the plus, otherwise this is probably mostly going to be a Regrowth. Can be better used somewhere that cares about the graveyard
? Omnispell Adept - Feels amazing when I can use it to cast a sorcery at instant speed or an expensive spell for cheap, but I don't have enough spells for this to work
Urban Evolution - Too many 5-drops and this doesn't have a huge impact. Card draw is nice though
Risen Reef - Nice to get extra lands if I know what's on top, but might not have enough impact
Alexi's Cloak - I'm probably better off just playing a counterspell
? Future Sight - Not sure I want to reveal my top to others, and it's expensive
Narset's Reversal - Do I have enough counters to make this playable? It's great to steal a Torment of Hailfire etc, though
Mystic Snake - Very expensive for a counterspell, but I do need some bodies, and being blinkable with Deadeye is great. Replaced with Rewind
Terastodon - Can I afford to deal out 3/3s? This guy doesn't have trample
Momir Vig, Simic Visionary - Might not have enough green creatures to abuse this