Snapcaster Mage - Great for replaying spells from your graveyard. This works well with cards like Consider. This creature can also act as a blocker if need be. There is a playset of them in this deck so you shouldn't feel too bad about sacrificing one in combat.
Thing in the Ice
- Good blocker in the early game. Becomes a can bounce the entire board later on and can act as a finisher all on it's own. Combos well with Snapcaster Mage, Narset, Parter of Veils, and Day's Undoing.
Brazen Borrower - Acts as an instant spell and as a creature. The early instant speed bounce coupled with a creature with flash, makes this card very versatile. Two mana to bounce a nonland permanent, three mana to play a creature at the end of your opponents turn, or five mana for both. The extra creature support makes it easier to damage your opponent (three flying damage every turn).
Narset, Parter of Veils - Makes it difficult for your opponent to keep up with your card draw. Is especially nice when paired with Day's Undoing. You will draw a whole new hand while your opponent will only be able to draw one card. Narset's activated ability is great for possibly searching up a Day's Undoing or a good counter spell.
Jace, the Mind Sculptor - Extremely useful and highly versatile. Jace's first two abilities are great for setting yourself up with a good hand while putting unnecessary cards back on top of your library. Jace, has the ability to protect himself with a built-in creature bouncer, it is entirely possible to bounce one of your own Snapcaster Mage or Brazen Borrower back to your hand. His last ability is essentially a game winner. Not much can be done once his ultimate has resolved.
Consider - Allows you to dig farther into your deck for the cards you need. The downside of putting a spell into the graveyard is neutralized when you got Snapcaster Mage in your hand.
Counterspell - Cheap counter. Allows you to stabilize early on. This card is great all game long and never loses it's potency.
Force of Negation - great counterspell for both the early and late game. The fact that it exiles the targeted spell afterwards is a nice feature (removes any possibility of your opponent reusing the spell). This card is strong at breaking combos, winning counterspell battles, and protecting your creatures from killspells even when you’re tapped out of mana (Tappedout! Sorry, had to).
Archmage's Charm - Amazing versatile spell. Having the options to counter a spell or draw cards at instant speed allows you to act depending on how your opponent plays the game. If they play nothing on their turn, then you can chance using this spell to draw more cards and "out card" your opponent. The the third ability is situational but it acts as a deterrent against modern staples (such as Aether Vial, Ragavan, Nimble Pilferer, and Dragon's Rage Channeler).
Day's Undoing - A nice reset card. Helps if you are running low on cards or if you want to save your graveyard. Also keeps your opponent from using graveyard combos. Pairs nicely with Narset, Parter of Veils.
Sea Gate Restoration
- A great versatile spell that can also act as a land. The extra option to lightning bolt yourself for an untapped land is pleasing especially if you are hurting for mana. The spell side to this card is somewhat situational. Usually you would only cast it as a spell if the game is going long and you need the extra cards to continue.
Hall of Storm Giants - This land is this deck's win condition. A heavy 7/7 creature with ward is no easy problem for your opponent to deal with, especially because this will be attacking during the late game when your opponent has fewer resources. This can also double as an excellent blocker if you are on the defensive. Because this land only becomes a creature for a turn and when it does it has ward 3, it becomes more difficult for your opponent to have suitable answers against such a threat.
Otawara, Soaring City - This land doubles as a spell in many regards. However, this card benefits from not being a spell (meaning it cannot be easily countered). This can act as a bounce spell for practically anything. Additionally, this card can bounce your own creatures and planeswalkers so that you may reuse their abilities.
Blast Zone - This land is an answer to pesky creatures that your opponent amasses. It is also useful against a handful of artifacts. The reason this land is important is that it is a permanent answer to a problem rather then simply acting as a bounce spell.
Gemstone Caverns - This land helps if you are up against an aggro deck. The fact that it helps you ramp on turn one means you can possibly have a Counterspell ready on your first turn. Obviously this only works if you are going second, but often being on the draw can be more beneficial for control decks anyway.
Riptide Laboratory - This land is perfect to reuse Snapcaster Mage's ability over and over again. in some cases, you can even flash Snapcaster Mage in, block, then use this land to bounce it back to your hand before the damage step (and you can cast a spell from your graveyard if you got any mana left over).
