stax in 2k19 lul
Watch the deck in action!:
https://youtu.be/PQ9WHZ8ORUk
And consider checking out other vids on my youtube channel while you're at it
Sideboard is stuff I want to test
Brago as a competitive deck is a stax deck (although I have a staxless control build which I've been pondering)
Your goal is to land an early hate piece or stax piece to stop or at least slow down combo decks - sphere of resistance, trinisphere, rest in peace, Ethersworn canonist - are good at doing this sort of thing.
While you want to get Brago in play as soon as possible, it can be hard to do this safely through countermagic, removal, or just losing to another deck while you've tapped out for Brago. If you're on a budget and lack fast mana rocks, it's especially difficult.
The deck also struggles with variability in mulligans. You need speed, which necessitates fast mana. You're also reliant on having some form of stax so you don't just lose (unless someone else at the table has you covered) and you likely also want some form of gas so you don't just stall out with Brago in play. Usually finding fast mana and some lands is good enough for your opening hand but too often you get slower hands that are painfully vulnerable.
This is largely why Brago has fallen out of favor in the competitive meta, aside from combo decks also being able to simply remove a stax piece and proceed to combo out.
The rest of your deck - the cards that aren't stax - is built around pushing an advantage with Brago out. You have cards that produce mana with Brago blinks (mana rocks), cards that draw cards or tutor cards with Brago out (eg. prophetic prism, trinket mage), cards that remove permanents when brago is in play (eg. Reflector mage, Rishadan Cutpurse), and some other utility.
Your artifact tutors will help you find answers as needed, such as tangle wire or cursed totem. Or they may find you a mana rock if you really need to. If you're in the right position, however, you can find Strionic Resonator, which is your main win condition. Strionic resonator, combined with mana rocks (or cards like cloud of faeries) producing 2 mana gives infinite blink triggers, allowing you to remove all permanents with rishadan cutpurse, draw infinite cards with prophetic prism, etc. If you produce over 3 or more mana, then you have infinite mana as well, but only in the combat step. Usually this means you'll draw your deck, create infinite mana, and use that mana to cast Venser ShaperSavant, which will let you bounce all permanents your opponents control - that should be enough to win the game, especially because you'll jam a sphere of resistance or trinisphere in postcombat.
Other ways to win include:
Rings of Brighthearth + Basalt Monolith combo - this generates infinite colorless, which is rarely enough to do anything with other than play out your hand. However, if you have Sensei's Divining top in your hand, you can proceed then to draw your deck and play whatever artifacts you want. A common way to assemble this is to play Tezzeret precombat, minus for Rings of Brighthearth, blink Tezzeret with Brago, activate again and copy the activation with Rings, finding both Basalt monolith and Sensei's Divining top. This line can be mana intensive but it's rather compact and clean - requires 3UU precombat and then 4 colorless post combat, in order to use Rings of Brighthearth's trigger twice. Trophy mage + blink is also great for this.
Stasis - Brago can pay the upkeep on stasis by blinking a colored mana producing rock. Meanwhile, he can untap all your other rocks too, so you actually have mana during your turn. Your opponents will be largely locked out in the meantime, and you can continue to draw cards and develop your board. However you generally want other effects in conjunction with this in order to really keep your opponents down, in order to prevent someone from simply removing Stasis or building up enough mana to get out.
Locking Down the Board - Stax pieces in conjunction with one another can form a difficult lock, keeping opponents from being able to cast spells or keep permanents in play. This is sort of the "snowballing" win-condition, where you shut down mana production with something like orb + tangle wire, then start bouncing or killing permanents with venser / pirates (Rishadan Cutpurse) / Similar effects