There are a number of characters you can play as from all across the 60-year history of the show, including many of the Doctors and companions

Ursulas Return Sapphire/Steel Hero Deck List Anna Braving the Storm (3x) Anna True-Hearted (foil) Aurora Regal Princess* (3x) (The First Chapter) Aurora Tranquil Princess (3x) Basil Of Baker Street* (2x) (Rise of the Floodborn) Flounder Collectors Companion (2x) Mickey Mouse Detective* (2x) (The First Chapter) Pascal Inquisitive Pet (2x) Prince Phillip Gallant Defender Rapunzel Appreciative Artist Sisu Wise Friend (2x) Transformed Chef Castle Stove (2x) Dig a Little Deeper (2x) Seldom All They Seem (2x) Aladdin Resolute Swordsman (3x) Ariel Determined Mermaid (3x) Hercules Beloved Hero (foil) Kida Royal Warrior* (3x) (Into the Inklands) Li Shang Imperial Captain (2x) Ling Imperial Soldier (2x) Mickey Mouse Standard Bearer (3x) Mulan Armored Fighter (2x) Philoctetes No-Nonsense Instructor Robin Hood Beloved Outlaw* (3x) (Into the Inklands) One Last Hope Smash* (2x) (The First Chapter) Imperial Bow (3x) Thebes The Big Olive (3x) Ursulas Return Sapphire/Steel deck review If the lack of synergy found in Amber/Amethyst (apart from the Encanto theming) isnt your thing, you might prefer Sapphire/Steel

Svyelun of Sea and Sky In my opinion, if you want to build a mono-blue merfolk deck, Svyelun of Sea and Sky is your best option for a commander
If your receive an uncommon ICR that's upgraded to a rare or mythic rare, and you already already have four copies of the upgraded ICR, the card will be replaced with Gems: 20 Gems for Rares, 40 Gems for Mythic Rares
This card is a huge payoff for +1/+1 counter effects, especially if you have cards like Good-Fortune Unicorn around