Frog Drop damage is calculated (Number of frogs Quina has caught x Quina's level), so at level 99, you would have to catch 101 frogs for Frog Drop to do 9999 damage every turn.

Thievery damage is calculated (speed/2 x number of items stolen) so you can raise it to 9999 damage every turn.

Dragon's Crest damage is raised permanately every time you kill a dragon, so kill enough dragons and you'll be doing 9999 damage with this one too.