A few tips for getting started with deck building
The cards in Feline Ferocity that most help the Go Wide strategy are the opposite of what the Go Tall strategy under Arahbo, Roar of the World wants: in this case, we want anthems that beef up our entire army (Hungry Lynx), cards that have triggers when a creature enters the battlefield (Qasali Slingers, and cards that care about the number of creatures we have (Kindred Summons)
A Tale to Astonish When Aaron Forsythe first came up with the idea of Universes Beyond , he collected his ideas in a presentation
Prophet of Kruphix has a similar untap ability, but when combined with the Prophets You may cast creature spells as though they had flash ability, the card was too good and was banned from Commander
Blue doesn't usually have a ton, but there are a few cards like Cloud of Faeries and Peregrine Drake that can go a long way with the help of mana doublers or Ravnica bounce lands