@Luffydom56 I think Thriller Bark has some of the best Zoro moments in general, and in my opinion, Zoro's best moments are his vice captain moments. The arcs prior to Thriller Bark do a great job developing Zoro as vice captain, while Thriller Bark gives us his ultimate vice captain moment.
Pre time skip gives us so many Zoro is the vice captain moments. In Alabasta, Luffy asks Zoro to save Smoker, and Zoro does so because he trusts Luffy's judgment regarding Smoker. Also in Alabasta, when Crocodile grabs Vivi off the sand crab, Luffy immediately throws her back to Zoro and tells him to take care of her. Luffy is able to handle the biggest threat because he trusts Zoro to take care of the rest. Throughout the arc, Zoro defers to Luffy and his judgment.
In Skypeia, Luffy also sees Zoro as vice captain because he trusts Zoro to take care of Nami, Robin, and Chopper during God's Judgment. Luffy is going to get his crew back, but he knows that they are safe with Zoro. Luffy doesn't need to tell Zoro do this or that, he just trusts Zoro to know what to do in different situations.
Next we have Water 7/Enies Lobby. By this point, Zoro is more comfortable speaking his mind regarding Usopp and Robin. He doesn't tell Luffy what he should do, but he does advise him. Then in Post Enies Lobby, Zoro is the one to give orders to Luffy. Luffy, whose skill is reading people, understands just how serious Zoro is regarding Usopp, so in return he listens and accepts Zoro's advice.
Back to Thriller Bark, after his fight with Moriah, Luffy is unconscious. To make matters worse, Kuma arrives and wants Luffy's head. With Luffy incapacitated, Zoro is the one who steps up and confronts Kuma because like Luffy, Zoro knows that Kuma is the biggest threat right now. Once Zoro realizes how strong Kuma is, he makes the decision to offer his life for Luffy and the crew as well. The reason I love this moment so much is it's because Zoro is finally stepping up as Luffy's vice captain. As stated before, Luffy trusts Zoro in terms of strength and judgment. I think the confrontation with Kuma is when Zoro realizes just how much Luffy trusts him to handle any threat and protect the crew. So he offers his life in exchange for Luffy and the others because that is what a vice captain does. He protects his captain even if it means the possibility of losing his own life. Zoro's journey and development as vice captain is amazing and Thriller Bark is the ultimate pay off.