I've found that this is an interesting deck to pilot. The core idea is to use the untap and loot triggers from Jeskai Ascendancy to dig through your entire deck with Sprout Swarm. Pair this with a mana dork and you can produce infinite mana for anything that you want to do. Especially difficult to pilot on MTGO, due to time problems.
Mana:
4x
Birds of Paradise
: The original and still the best.
Noble Hierarch
is all very well and good but if you're attacking for anything less than lethal then you're doing things wrong anyway so the exalted on hierarch really doesn't matter and, critically, birds can produce where hierarch cannot. Flying can also be relevant in some corner cases, both for sneaking damage past blockers and for chumping in a bad spot.
3x
Sylvan Caryatid
: The unboltable bird. Will be worse than hierarch in some cases, and could be swapped out, but a 0/3 blocker can be super relevant in some cases and having a mana dork which doesn't die to most removal is great. Also taps for .
1x
Dryad Arbor
: Playing lands that can be bolted is typically a bad idea, but here you're playing a fetchable land (both with fetchlands and with chord, both of which can be useful) that untaps with every Jeskai Ascendancy trigger. Makes comboing off easier.
Control Tools:
3x
Electrolyze
: An efficient and versatile control tool which also functions as the deck's primary win condition. When you have infinite mana and looting you can point these at your opponent's face until they're dead.
3x
Lightning Bolt
: Bolt is bolt. What more needs to be said? It kills birds. It kills bobs. It probably kills something in every deck you're going to play against.
3x
Opt
: Card selection which is also a 1-mana instant (the importance of which will be explained later). Beats out
Serum Visions
because you can hold it up along with Remand and it allows for immediate card selection which can really save you in a bad spot.
3x
Path to Exile
: White bolt kills anything that bolt can't. Goyf bothering you? Path. Death's Shadow? Path. Go on, get a land, with any luck you won't get to untap it anyway.
4x
Remand
: You're playing a combo deck, so Remand is better than
Mana Leak
(and would be even if leak always worked as intended) just because drawing extra cards is so useful.
The Combo:
4x
Jeskai Ascendancy
: This card does everything you want it to and more: every noncreature spell you cast loots you closer to a Sprout Swarm and once you get one you can go infinite by using the convoke and buyback on swarm to untap your tokens and then tap them again to recast swarm. Draw and cast Elecrtolyze at your opponent's face until they are dead. Remember that every noncreature spell you cast essentially generates one mana for each mana dork you have in play, so 1-mana spells like bolt or Opt can net gain you mana when you have more than one dork (or more than one ascendancy). This card is also the only good way to get Emrakul out of your hand, which is somewhere you really don't want it to be.
4x
Sprout Swarm
: A durdley card that is almost entirely useless in the deck when you're not comboing off. However, it can be worth hoarding them in your hand to play around counter magic, and don't forget that this card doesn't have to cost 5: sometimes a 1/1 for 2 is good enough to get something done.
1x
Emrakul, the Aeons Torn
: A card you should never have to cast. I know it seems tempting, but put down that 15 mana! The easiest way to fizzle with this deck is to end up with your Emrakul in the wrong zone for some strange reason. Yea, yea I know. Nobody plays
Mindbreak Trap
any more. Just don't take the risk, it isn't worth it. Copyright-Free Cthulu's only job in this deck is to let you shuffle your graveyard back into your library. This lets you draw as many copies of Electroyze as you want, or recur anything else you might have pitched over the course of your combo.
Insurance:
1x
Chord of Calling
: I know what you're thinking. "A deck with Chord of Calling and Emrakul in it: the plan is obvious right?" Wrong! Chord is in this deck because you might very occasionally find yourself comboing off without a mana dork to actually generate mana for your burn spells. Chord is the zero-mana spell which turns your saprolings into birds. "But wait!" I hear you commenting, "Birds don't have haste!". Well, dear reader, you'd be right. But you know who does have haste?
1x
Samut, Voice of Dissent
: Ok, it's a long shot, but after you've chorded for a bird you can reshuffle the chord with Emrakul and chord for Samut to give it haste. Samut also does double duty as a double striking 3/4 flash, which might occasionally confuse the bejesus out of your opponent who thought they had your stupid combo deck figured out.
1x
Pull from Eternity
: No! Keep reading! I've not gone completely mad (or, at least, no more mad than the rest of this deck). Pull from Eternity is the only card which does what it does and it does it with startling efficiency. Quite apart from making
Ancestral Vision
players cry and saving you 3 life against
Rift Bolt
from burn (oh who am I kidding? Burn is a horrible match-up either way), pull can save you from graveyard hate like
Rest in Peace
and
Scavenging Ooze
. Even in the worst case scenario (where Think Twice and Vanish into Memory are both exiled) pull and three other random cards are all you need to deal with something like rest in peace, simply deal with the source of the graveyard hate by looting and exiling stuff that isn't pull until you find an answer, then pull your Emrakul back into your graveyard and loot until you turn one of your last two cards into pull. Then pull Vanish into Memory and loot to turn your last card into Vanish. Cast Vanish on a saproling to draw as many cards as you need and repeat until your entire deck is back where it should be!
1x
Sundering Vitae
: More strange cards! What looks at first like a 3-mana
Naturalize
is actually a 0-mana Naturalize, which is vital if you're trying to go off through a Rest in Peace and have no mana dorks to do it with. Simply loot for vitae and reset as described above before fetching your mana dorks and Samut with chord.
1x
Think Twice
: This card is fine. It draws a card now and another later, both at instant speed. It also triggers ascendancy twice, but that's not why it's in the deck. It's in the deck because one way to fizzle with this deck is not to have enough cards in hand to actually cast anything as you're looting. As long as you haven't flashed Think Twice back yet you can loot through it then skip the first round of thinking to immediately draw a free card which can be looted into Vanish into Memory for some real card draw.
1x
Vanish into Memory
: Removal that draws you cards. What's not to like? Maybe the 4 mana price tag, but that doesn't matter mid-combo: the magical land where everything is functionally free. Vanish into Memory is the best way to net gain cards mid combo so that anything you cast that isn't a cantrip can replace itself. Just target one of your saprolings and draw as many cards as you like (remember that ascendancy buffs them up to unreasonable sizes). Can also let you dig a fair distance into your deck and blank a threat so you have the time and cards to assemble your combo, which is particularly good against aggressive decks where powers might exceed toughnesses anyway.
