Below is a step-by-step guide on how to get more than 303 mana on turn 3.
For this, I will be sideboarding in
Garruk Wildspeaker and
Paradox Engine, and borrowing
Birds of Paradise,
Karametra's Acolyte,
Voyaging Satyr,
Fervor, and
Kiora, Master of the Depths from the maybeboard. Also, this does not account for card draw, meaning that if you have a 7 card hand and you draw 1 card every turn, this won't be possible. In addition, on turn 2,
Arbor Elf is tapped, even though it has summoning sickness. Taking all, of this into consideration, **it is not realistic to get this to happen in a real game**, and this is all just an amusing speculation.
Turn 1:
Forest, tap it to play
Arbor Elf.Turn 2:
Forest, tap it to play
Utopia Sprawl, enchanting untapped
Forest. Tap enchanted
Forest to play
Birds of Paradise and another
Arbor Elf. Tap
Arbor Elf to untap enchanted
Forest. Tap enchanted
Forest to play 2 more
Utopia Sprawls, enchanting same
Forest. Now, tapping that
Forest will give you
. Turn 3:
Nykthos, Shrine to Nyx, tap
Birds of Paradise and enchanted
Forest for
. Use
to play
Fervor and use the other
to play a 4th
Utopia Sprawl (enchanting same
Forest) and a 3rd
Arbor Elf. Tap enchanted
Forest for
, and use it to cast
Paradox Engine. Tap
Arbor Elf to untap enchanted
Forest, then tap enchanted
Forest for
. Use
to cast
Elvish Archdruid, untap all
Arbor Elfs, and use the
to cast the 4th
Arbor Elf and
Elvish Mystic, untapping all your elves again. Tap 3
Arbor Elfs to untap enchanted
Forest 3 times, creating 15 mana. Use 9 of the 15 mana to play 3 more
Elvish Archdruids (4 are now on the battlefield), again, untapping all your elves. Cast 2
Khalni Hydras from your hand for free. Tap
Birds of Paradise for
and
Elvish Mystic for
, so now you have
because of the 6 leftover mana. Use all 8 mana to cast
Garruk Wildspeaker and Kiora, Master of the Waves:. Tap
Elvish Archdruid (for 9) again to cast
Karametra's Acolyte and
Voyaging Satyr, leaving
floating and untapping your
Elvish Archdruid. Now, tap
Nykthos, Shrine to Nyx for 39 mana. Tap
Voyaging Satyr to untap
Nykthos, Shrine to Nyx, then tap it for another 39. Tap
Karametra's Acolyte for 39 mana. Use the +1 of
Kiora, Master of the Depths to untap
Nykthos, Shrine to Nyx and
Voyaging Satyr. Tap
Nykthos, Shrine to Nyx for 39, untap it with
Voyaging Satyr, then tap it again for another 39 mana. Tap enchanted
Forest for
, then use the +1 of
Garruk Wildspeaker to untap enchanted
Forest and
Nykthos, Shrine to Nyx. Tap
Nykthos, Shrine to Nyx for 39. Tap
Elvish Mystic for
and tap
Birds of Paradise for
. Tap enchanted
Forest for
, untap it using the first
Arbor Elf, tap enchanted
Forest for
, untap it using the second
Arbor Elf, tap enchanted
Forest for
, untap it using the third
Arbor Elf, tap enchanted
Forest for
, untap it using the fourth
Arbor Elf, and tap enchanted
Forest for
. Tap regular
Forest for
. Tap each
Elvish Archdruid for 9, adding a total of 36 to your mana pool. 39*6+36+25+5+2+1= 303. But, don't forget
Paradox Engine. Untapping all your creatures, then retapping them again would give you an additional 135 (39*2+36+20+1). So, if y is the number of spells you play with 303 mana, then by doing this, you can get 303 + 135y!