Four mana to make an opponent discard one card and draw one for you wasnt great
This is why Sin puts counters on another creature and then shuffles itself into the library, representing the Calm before its eventual return
Even just +2/+2 and protection from two colors is a huge problem in a lot of games with everyone playing two color decks, theres a pretty good chance Red or Green is one of their colors
Mystical Teachings Mystical Teachings is a staple from control decks of old, and it gives you a mana sink for card advantage, as well as an extra tutor for instant-speed interaction spells or a flash threat
Most of that stuff is just copyright info, but the information to the right of that line is what is known as the collector number, and it tells you where the card falls in the set, should you wish to organize your collection in that fashion
Mono-blue decks should lean heavily on 2-mana rocks (8-10 pieces minimum) since blue lacks natural land acceleration, with Arcane Signet, Mind Stone, Sky Diamond, and Thought Vessel forming your core