Check out my expensive, yet technically still f2p valkyrie deck, i'm glad to say i haven't payed at all to get these. They got me to kog and lvl max against top
Valkyrie Dritte - Yugipedia - Yu-Gi-Oh! wiki
Yu-Gi-Oh! TCG Deck - Kelly's Valkyrie Deck by Kelly Locke | TCGplayer Infinite