Starting with a mechanic idea, it felt straightforward to create some cards with the mechanic and/or that supported the mechanic, then add some generic cards like removal spells and simple creatures
Shoot the Sheriff Shoot the Sheriff is very similar to other 2-mana restrictive black removal spells
The top two recommendations on that list Dragon Shield sleeves and Titan Shield Premium sleeves are both available in a range of coloured sleeve types, so you can be sure to keep your upcoming double faced cards hidden until they need to be used
If you never plan on attacking with the birds, keep in mind that Luxray GL LV
If your opponent is in red, the burn spells generally do 3 or 4 damage such as Fire Prophecy and Flame Spill, so if you want to avoid that, you'd want to put a 5 toughness creature on top
Much like Scar, Mastermind - an underrated Amethyst card from The First Chapter, Maid Marian has an on-play effect that can take your opponent by surprise, giving you a chance to trade with their board for free, and establish a well-statted character that can start questing the very next turn