The first image shows the horizontal split, and your sideboard is in the right corner
It rewards players for building hyper-specific plans around favored cards, and makes you feel like you, personally, are the genius behind a beautiful snowflake of a deck
It has indestructible, you'll gain protection for the round if you cast it, even from exile works, and then you can tap it to toss a burden counter, draw that many cards, and in your upkeep you'll lose burden counter life
This can be quite powerful, as seen with other popular storm spells like Brain Freeze, Grapeshot, and Flutterstorm, and while storm is a strong keyword to have, it's not readily available on many cards
Malcator's Watcher This is yet another option that looks like it could fit well into Affinity-style strategies, but probably is too weak to make the cut
Umbris is a 1/1 Dimir creature for five mana that exiles cards from your opponents libraries whenever a horror or nightmare enters the battlefield