mtg sivitri dragon master commander deck EDH Deck Sivitri, 100 Magic Cards – Moonveil Games Dragon creatures Commander Sliver Deck Sivitri, Dragon

Recruiter of the Guard makes those decks dramatically more consistent by turning one creature into the exact next creature you need

Nearly all of its cards synergize with Atraxa, Praetors' Voice and you can consistently always cast your commander on turn 4 with an excellent mana base

There are a few more of these things at Rare and Mythic, but you get the picture this kills almost everything incredibly efficiently

In the long term, I would recommend Commander players pick up a copy of Nibelheim Aflame at some point

2019-05-03 After you draw a card as Nicol Bolass first loyalty ability resolves, the next opponent in turn order (or, if its somehow an opponents turn, that opponent) chooses a permanent they control or chooses a card in hand without revealing that card