Card support beyond Tag Team Cards

"With the release of the latest Pokémon TCG expansion, Sun & Moon—Team Up, you're undoubtedly hearing a lot about the new TAG TEAM cards that add a whole new element of strategy to the game. But with all the excitement surrounding those cards, let's not forget all the other fantastic cards that you'll find in this new expansion. Take a look at some of the other useful cards that will boost the power of your deck." - from the pokemon Website

This states that even through the power of the introduced Tag Team cards, there are plenty of other core-support cards that were introduced as well.

Prism Star Cards

"Prism Star cards continue to be mighty additions in the Sun & Moon—Team Upexpansion. Tapu Koko Prism Star, for example, makes an impact with its Dance of the Ancients Ability, which lets you attach a Lightning Energy from your discard pile to 2 of your Benched Pokémon, if Tapu Koko  is also Benched. Tapu Koko must then be placed in the Lost Zone, and any cards attached to it get discarded." - Pokemon Website

These rarities give you the chance to use powerful abilities to support your deck's strategies. For example, Tapu Koko is an extremely useful support card for the Marshadow/Vika Volt deck.

This favors a return for the lost zone, which has existed all the way back in Diamond and Pearl.