You can select them in any ways you wantmaybe you just like those colorsbut three things to keep an eye out for are: Any strong rares in those colors that you're excited to play A lot of removal cards (Cards which destroy or otherwise deal with your opponent's creatures.) Evasion (A lot of Sealed Deck games are won with flying creatures or hard-to-block cards.) Additionally, another huge element to look out for are good synergies and multicolor cards
Thank you for bringing this up, and I'm glad you like this
Imagine this card: Big Man Down Sorcery Target player reveals his or her hand and discards the card in their hand with the highest converted mana cost
For a birthday party, you could create a card featuring the birthday person and give one to each guest, or create a set of cards featuring every guest
King, Seed Cursed ability now deals 4 damage Demonic Contract now cost 1B The Ethics Committee sacrifice protection is now delayed to the end of the turn Yash, Profane Dark now cost 1BB and has 2 power Dr
The chosen recipient must be able to legally be enchanted by the Aura, so a player or permanent with protection from one of the Aura's qualities can't be chosen this way