It doesn't end there either, as the first creature spell you cast at the beginning of every turn has its mana cost reduced by two, thanks to Conduit of Ruin
(Each booster pack contains 10 game cards, 1 Basic Energy, and 1 Pokmon TCG Live code card
In a similar sense, I think that if we are working with self milling cards or just a high ratio of spell cards in general, then Psychic Spiral can itself be a powerful win condition to reach a similar goal as the previous examples
Electric Jellyfish X WATER Level 4 [ AquaEffect ] ATK 1400 DEF 1700 You can send 1 "Umi" from your hand, Deck, or face-up field to the GY
Sunken Palace Sunken Palace takes time and setup to use effectively, but when the moment hits, that bonus mana can fuel some dramatic plays