Shere Khan, Menacing Predator is a great card to put out whenever youre in a strong position to challenge your opponent, which should happen often if youre playing with ruby cards
Being an incredibly powerful card in standard, Badgermole Club can provide some immensly powerful early game wings, allowing you to set up a board stage with little additional effort
Keen Sense Curiosity-style cards are always interesting and playable in blue, and Keen Sense is like that but in green
Thanks to the command damage rule, it becomes trivial to deal large outbursts of damage with Korvold to take someone out of the game with 21 commander damage
This should hopefully help bulk out and refine your deck, with a few more powerful cards that arent to be scoffed at
It has Flash and, when your opponent casts a tutor or a card that lets them look through their deck (maybe the ever-present Cultivate or the iconic Demonic Tutor), he'll give you one life and draw you a card