A cheap card like Sleep Magic is a good way to stall powerful opposing creatures, or you can eliminate them with something like Overkill
When paired with Lorcana cards that can heal him or any other character with the Support ability (adds their strength to a chosen card when they quest), Olaf can actually become a very powerful card very early on
These can be paid for like any other card, but can also be sung by a character you already have on the table if they meet the songs ink requirements
Combine the massive dragon with purple cards such as Merlin, Goat or Yzma, Scary Beyond All Reason to pull them off the table, ready to be played again and reactivate their own powerful effects.
You send them some options, see what they like, and work from there
Many in the early community thought there could be space for a sixth, hidden rarity