Five mana is a bit costly, but in a dedicated flying deck or an Orzhov afterlife deck, an evasive army of boosted creatures could close out a game with little problem
If the target player is an illegal target by the time Ukkima's last ability tries to resolve, the ability won't resolve
That's right: carefully choosing the booster pack you want to open from the game's carousel doesn't matter
You can use Zeraora to generate free Lightning Energy through its ability, retreat it after using its 2 Energy attack (using X Speed), and then employ an Elemental Switch to transfer Lightning Energy to Dragonite EX or a Lightning-type Pokmon
Mycosynth Lattice There are easier ways to lock players out of a game, but Mycosynth Lattice does the trick with any card that stops activated abilities from artifacts
When it enters the battlefield, you get a three-time boon that lets a merfolk explore whenever another one enters under your control