We all know that the Mono Blue Tempo is one of the consistent Standard decks as per the current metagame, not to mention winning the first Mythic Championship. Looking for an additional arsenal of the deck in War of the Spark, I have found one particular card that can be a sideboard option for the heavy-removal matchups. Presenting, Kasmina, Enigmatic Mentor.
The static ability gets her protection to tax removals such as Vraska’s Contempt and of course also on your creatures. Her minus ability fits well to my mentioned matchup as she can produce a threat whilst giving you card advantage to be able to dig for your threats or answers. The four mana cost looks already fair for an Uncommon card.
If permits that she may become of the Rare type, I might want to add a +1 loyalty ability that gets you to Scry cards or bounce stuff. For now, she is a solid one copy mainboard and maybe two more copies in the sideboard. We will see how it goes once the set is legal in Standard to play.