What will be sideboarded out
Hedron Alignment - Most important card game 1, this is your bait (and your disrespect). This is your win if your opponent has locked you down or you are so far behind but can somehow pull this off. This is your plan B. You shouldn't be directly aiming to win with this, but you do need to keep an eye on it so you have the option. This is sideboarded game 2 as your opponent will believe this is your plan A and no one expects you to be able to change your wincon with a sideboard.
Secret Salvage - The card that actually gives you a decent chance of pulling off an alignment win, if you have 2 alignments in the graveyard this actually puts your opponent on a decently small clock. Sideboarded with the alignment to give you more wincons to side in (granted I guess you could leave it in for the Scourges or Griffens). Run at 3 since you never really want more than 1 in your hand.
Creatures
Wharf Infiltrator Your only real way to get cards from your hand into your graveyard (only other real way is your opponent forcing you and having 8 cards and discarding, I've had to do that, fun times....). It is usually unblockable as most things in modern don't have 1 power and if they do they won't be blocking. The tokens are just a plus side and usually help lower the damage you will be taking early game.
Eternal Scourge,Misthollow Griffin,Torrent Elemental - Putting these all here because they are all here for the same reason. These are the 3 creatures you can cast from exile. As you will be constantly delving to kill your opponents field, this let's you get more value out of your creatures. Plus, it makes your opponents Scavenging Ooze slightly a double edged sword and makes Path to Exile an unsummon with you getting a land.
The Scarab God
- This is primarily your game ender game 1 (and even the games after that). At the worst you exile your own creatures, send them to exile, then recast them (4/4 flying griffin with his friend coming shortly is pretty nice). Plus you can start stealing the creatures from your opponents graveyard. Always nice to take a Spell Queller when your opponent tries to cast something or take that Grim Flayer and making it a 6/6. Only ran at 1 because I got lucky with a pack.
Mainboard Planeswalker
Kiora, the Crashing Wave - This deck has 61 cards as a sign that this is made for fun, if you want this to be serious then this is the card that will most likely be taken out. I playtested a decent amount of planeswalkers and this Kiora was the first planeswalker that I drew and got to win a game game 1 so it takes the 61st spot. This deck is quite good at stalling and kiora's ultimate can drastically turn a game to your favor. Her middle effect isn't anything noteworthy in this deck but the plus one does help keep her alive (plus you can target your opponent's land to let them know you mean business).
Removal
Yahenni's Expertise - This is your primary board wipe, You could run languish or damnation instead but 1. The scarab god, his tokens, and torrent elemental don't die to Yahenni's, and2. Damnation is a bit pricey (no where near some other things, but still)Plus the free 3 or less drop can be useful for digging through your deck with Taigam's or Forbidden Alchemy (or a Liliana of the Veil or Liliana, the Last Hope if you have those).
Murderous Cut - Your a deck trying to get things in exile and this is a kill spell that does that, a decent amount of people expect the bolt or push and think their creature is safe but this helps keep them in line.
Dead Drop - It's amazing that the amount of times I say the words "I delve for 9 and-" and the people playing the game right next to me stop what they are doing and look over. NO ONE expects this card. Why yes, it is a 10 drop, but it has delve, and you won't be casting this for 10 mana, you will probably be casting it for 5 or less. This is usually a very strong turn 3 (if you've been able to throw a lot in the graveyard) and drastically sets more midrange/aggro decks back. Not to mention that usually people will plan on 1 sacrifice, not 2. Don't underestimate this card.
graveyard activators
Vessel of Nascency - This is just here because it's one of the few green cards that throw cards to your graveyard that has the words "planeswalker" and "enchantment" written on what you can grab. If you are going a more aggro route then replace this with Grisly Salvage.
Forbidden Alchemy - Very similar to the Vessel above, this is here because you can grab any type of card with it while also increasing your graveyard. The flashback and it being an instant are quite the bonus as well.
Taigam's Scheming - This right here is one of the most under appreciated cards ever printed in my opinion. For 2 mana you effectively scry 5 just that instead of going on the bottom of your library they instead go into your graveyard, as in, they become more resources. This helps you dead drop and murderous cut early game as well as throw away unneeded draws. Plus, almost no one will Inquisition or Thoughtseize it because it's a 10 cent card and therefor worthless.
Lands
Lands are just what I have, fetches are pretty good since they go to your graveyard and that helps delve, scry's I've found are actually pretty good at helping you plan ahead, but if you have the money you can probably do a much better land base, I've just gotten lucky with some pack pulls.