What is the fastest way to get infinite mana in Historic?

Question

I'm looking for the combo using the fewest cards from the start of the game that allows you to generate unlimited mana using Historic-legal cards. It doesn't have to be viable or practical, but I have two restrictions:

1. No using Codie, Vociferous Codex, because I need to cast permanent spells for what I'm trying to pull off and Codie doesn't allow that.
2. The opening hand may be assumed. If a solution requires more than 7 cards, you may assume perfect results from random events. If it requires 7 or fewer cards it must be deterministic.

I devised a method using 11 cards over 4 turns, requiring you to be on the draw and draw perfectly.

1. Play Botanical Sanctum and tap it to cast Llanowar Elves
2. Play Lotus Field, tap Sanctum to cast Stifle targeting Lotus Field's trigger, and tap one Llanowar Elves to cast another
3. Play an untapped land, tap everything to cast Chromatic Orrery, tap it for 5 to cast Irencrag Feat, then spend that mana to cast Nyxbloom Ancient
4. Cast Circle of Dreams Druid and enchant it with Gauntlets of Light

I'm sure this can be improved.

Answer 1

Try #2: Turn 3, 7 cards

1. Forest, Llanowar Elves
2. Land, Selvala, Heart of the Wilds
3. Swamp, Rotting Regisaur, Tap Selvala for 2W2WG, play Gauntlets of Light, untap Selvala, tap Selvala, repeat

Try #1: Turn 3, with 10 cards

1. Forest, Llanowar Elves
2. Lotus Cobra, Forest, Lotus Cobra
3. Forest, Ashaya, Soul of the Wild, Lotus Cobra, Lotus Cobra, Man-o'-War, Man-o'-War, Man-o'-War, Man-o'-War...

Explanation: Man-o'-War can bounce itself. With Ashaya out, Man-o'-War is a land. With four Lotus Cobras out, Man-o'-War entering the battlefield produces 4 mana, but it only costs 3 to replay.

Answer 2

Turn 2, 7 cards or turn 3, 6 cards!

(This solution has been improved, but I'll keep the answer around because the optimal one only gives red mana.)

Turns out it was very easily improvable! A card is saved in the turn 2 and 3 deterministic categories!!

0. Begin the game with Leyline of Abundance in play.
1. Play Temple Garden paying the 2 life and cast Gilded Goose.
2. Tap Garden and Goose for G+RG (thanks to Leyline). Cast an Incubation Druid. Cast Kick in the Door targeting the Druid. Tap the Druid for WWWG and enchant it with Gauntlets of Light. Either cast Stony Strength to untap the Druid or pass the turn.

Turn 2, 8 cards or turn 3, 7 cards (source: reddit)

0. Begin the game with Leyline of Abundance in play.
1. Play Temple Garden paying the 2 life and cast Gilded Goose.
2. Tap Gilded Goose for U+G (thanks to Leyline). Cast Neoform on Goose to fetch an Incubation Druid. Play an untapped red land (e.g. Spirebluff Canal) and cast Claim the Firstborn on the Incubation Druid. Tap the Druid for WWWG, then enchant it with Gauntlets of Light.
3. Either cast Stony Strength with your one remaining G to untap the Druid or pass the turn.

This combo uses only cards that were Standard-legal at the time of its posting two years ago. It might still be improvable.

Answer 3

1 turn, 8 cards from hand + 2 from library

Forest, Oviya Pashiri, Sage Lifecrafter; 3×Mox Amber, tapping each for {G}; Burning-Tree Emissary, after which one has {R}{G}{G}; Chaos Warp targeting Mox Amber, putting Omniscience onto the battlefield.

Now cast Acererak the Archlich repeatedly, going through Lost Mine of Phandelver and getting a Treasure each time. This is not quite infinite yet because that dungeon also makes one draw a card each time, so add Ormos, Archive Keeper to stop that from causing a loss and make it truly infinite.

1 turn, 18 cards, relying only on drawn cards

Phyrexian Tower, Ornithopter; tap Phyrexian Tower and sacrifice Ornithopter for {B}{B}. Divest to discard Kinnan, Bonder Prodigy, then Claim to return Kinnan, Bonder Prodigy to the battlefield. Mox Amber and tap it for {U}{U}. Myr Scrapling, then Of One Mind to draw 2.

(Mox Amber (previous Mox is sacrificed due to the legend rule), tap for {U}{U}, Of One Mind)×3, ending up with 3 blue mana and 2 cards in hand. Scrap Trawler. Sacrifice Myr Scrapling targeting Scrap Trawler, triggering Scrap Trawler to get back a Mox Amber; cast and tap it for 2 mana. Chromatic Sphere and sacrifice it, getting 2 mana because of Kinnan, Bonder Prodigy, drawing a card, and getting back Mox Amber with Scrap Trawler, for another 2 mana. Cast and sacrifice another Chromatic Sphere, but this time hold on to the returned Mox Amber. (Now 4 mana – make some of it white – and 1 new card in hand.) Teshar, Ancestor's Apostle. Now loop: cast Mox Amber and return Myr Scrapling to the battlefield with Teshar, Ancestor's Apostle, tap Mox Amber for 2 mana, then sacrifice Myr Scrapling and get back Mox Amber with Scrap Trawler.

2 turns, 9 cards

Turn 1: Forest, Gilded Goose, Mox Amber.

Turn 2: Aether Hub. Tap the lands and spend the Energy for Kinnan, Bonder Prodigy. Tap Gilded Goose and sacrifice the Food it created for {R}{R} to cast First Day of Class. Tap Mox Amber for {G}{G} to cast Incubation Druid, which gets haste and a +1/+1 counter. Tap it for {U}{U}{U}{U}. Cycle Vizier of Tumbling Sands to untap Incubation Druid, with {U}{U} left, and tap it again for {W}{W}{W}{W}. Now cast Gauntlets of Light on Incubation Druid, and repeatedly untap and tap it to get infinite mana.

Also 2 turns, 9 cards

Turn 1: Forest, Gilded Goose, Mox Amber.

Turn 2: Island. Tap the lands for Kinnan, Bonder Prodigy. Tap Gilded Goose and sacrifice the Food it created for {R}{R}, and tap Mox Amber for {G}{G}. Spend {R}{G}{G} on Xorn and the remaining {R} on Strike It Rich, producing two Treasures. Sacrifice the Treasures for 4 red mana and spend 3 to cast Strike It Rich again by flashback for another two Treasures, and sacrifice those, for a total of 5 mana. Cast Goldspan Dragon and have it attack, producing two Treasures that can now make 3 mana each, for a total of 6 mana. Cast Conviction on Goldspan Dragon, producing another two Treasures, and return it to hand with its ability, and repeat for infinite mana.

Answer 4

Turn 3, 5 cards!

0. Begin the game with Leyline of Abundance in play.
1. Play a Forest and cast Llanowar Elves.
2. Cast Sanctum Weaver.
3. Tap all permanents for G+GG+WWG. Enchant Sanctum Weaver with Gauntlets of Light. Untap it. It now taps for WWWG.

Turn 3, 6 cards!

I have saved a card in the turn 3 deterministic category!!

1. Play Blooming Marsh and cast Llanowar Elves.
2. Play Plains and cast Faeburrow Elder.
3. Tap Blooming Marsh to cast Footlight Fiend. Tap Faeburrow Elder, Plains, and Llanowar Elves for 6 mana, BRGW+W+G. Enchant Faeburrow Elder with Gauntlets of Light and untap it.

Many thanks to reddit user GreenNinjaDa, the author of the solution in my other answer, who told me about Faeburrow Elder and inspired me to find this solution.

I was unable to adapt this solution to save a card for turn 2 deterministic, but luckily I found a different way to do that! Check out my other answer.

Answer 5

Turn 2, 6 cards!!

As is often the case, the final improvement came from an angle one would never expect (which is why this merits its own answer). Infinite thanks to reddit users ava-fans and MoshiMaro in this thread for giving me the pieces to find this!

1. Play a Mountain and cast Skirk Prospector.
2. Play Phyrexian Tower. Cast Ornithopter and sacrifice it to Phyrexian Tower for BB. Cast Putrid Goblin. Tap Mountain and sacrifice Putrid Goblin to Skirk Prospector for RR. While Putrid Goblin's Persist trigger is on the stack, cast First Day of Class. Now Putrid Goblin will return to the battlefield with both a +1/+1 and -1/-1 counter on it, allowing us to repeatedly sacrifice it and add as much {R} as we want.