YGO: Hidden Summoners Booster Box - Rules of Play says:
Yu-Gi-Oh! TRADING CARD GAME Hidden Summoners is Fall 2018’s 60-card, all-foil booster set, and it’s packed with 3 new Deck themes that use multiple Summoning methods! Each Deck strategy introduced in Yu-Gi-Oh! TRADING CARD GAME Hidden Summoners combines the flexibility of Link Summoning with the raw power of another type of Special Summon.