If youre new, Tribute and Special Summon mechanics are classic Yu-Gi-Oh
Luffy from Emperors in the New World [OP-09] and Charlotte Linlin from Two Legends [OP-08] can be brought in for their highly powerful effects, as can the Gum-Gum Giant card from Emperors in the New World [OP-09] which serves as a draw engine and also raises the Power level of either the decks Leader card from Awakening of the New Era [OP-05] or any of its Character cards by 4000
After Link Monsters were introduced, monsters from the Extra Deck could only be Special Summoned from the Extra Deck to the Extra Monster Zone, or a Main Monster Zone a Link Monster "points to", up until the rule change for April 2020 onward, where only Link Monsters, and Pendulum Monsters Summoned from the Extra Deck while face-up, follow this restriction
This was especially valuable in the early days of One Piece, when hand-filtering effects weren't as common
With 120 cards in total across all three sheets, theres a wide range of cards you can open in this slot