Blue, Loyal Raptor Legendary Creature Dinosaur Partner with Owen Grady, Raptor Trainer (When this creature enters, target player may put Owen into their hand from their library, then shuffle.) For each kind of counter on Blue, Loyal Raptor, each other Dinosaur you control enters with a counter of that kind on it
If you don't remember any blue knights you have access to, try Cavalier of Gales, Thistledown Liege or Herald of Hoofbeats
Magic Origins also returned with double-faced cards, but this time the backsides were all planeswalker cards
Personal Reasons due to personal taste, change of mind etc
Three-color legends tend to be popular Commander options, and this one offers a lot of potent text for Spellslinger decks