Sealed Memories works in perfect synergy with Sweet Breaker and can act as Melting Memories on a specific opponent. It also does little harm if Sweet Breaker herself lands on it.
Cards with high star costs/levels or effects that make them difficult to use such as For the Future of the Toy Store and Princess's Privilege can be used to great effect with Sweet Breaker's hyper as the opposing player will be unable to use them. Caution should be taken with Princess's Privilege as the effect can backfire with the opponent using it to empty their hand of reversed cards.
Reverse Attribute Field can be used effectively with Sweet Breaker. Since she herself is immune to the card, it can be used to great effect to weaken opponents such as Boss characters.
Sweet Breaker can get some of the most use out of Extend as it counters her poor REC stat.
Sweet Breaker can also benefit from President's Privilege as at its maximum, her hyper can cost 45+ stars.
Play of the Gods can also be used with the hope of activating Sweet Breaker's Hyper cheaply.
Using Party Time after reversing their cards could be considered monstrous if the players don't get away.
As most of Sweet Breaker's strength is derived from the other player possessing cards, some of the most effective cards against Sweet Breaker are cards that cause both her and the player to discard cards. Cards such as Flamethrower and Scrambled Eve can leave Sweet Breaker with less options and no stat boosts.
Sealed Guardian and Forced Revival are also good counters against Sweet Breaker as they strip away her health, leaving her vulnerable to most attacks and in even worse shape as a result of her poor REC stat.
The player should try to lessen the power of Melting Memories in the sense that they can purposely discard cards to lower Sweet Breaker's increased stats and make the cost spent on the Hyper pointless.