A simple cardboard box with dividers are cheap and get the job done, more or less, but a soft interior can really help prevent any further damage to your expensive Magic cards
If other cards affect dragons and/or skeletons, we know they'll affect Bone Dragon
Giving your creatures first strike makes them much more likely to survive two combats, or at least trade at a profit, and having your extra combat stapled to a 5-power creature pushes a lot of damage
Cards like Avacyn, Angel of Hope and Throne of Eldraine are too much to expect from such a cheap product, but there are many angel staples like Lyra Dawnbringer, Starnheim Aspirant, and Sephara, Sky's Blade that would be reasonable inclusions
Paying 4 mana and sacrificing something to potentially just win the game with the right 4 mana or less card from your deck (and there are a lot of cards that can do that) is an amazing bargain, and you can run 4 of them, meaning that the combo piece you needed