Minecraft wiki entry for Complete_main_adventure, associated text: At least 2 stacks of obsidian
A netherite sword with Sharpness V, Looting III,Mending and Unbreaking III.
A bow with Power V should also be enchanted with Infinity.
Snowballs or eggs (bring only if the bow is not enchanted with Infinity) to throw at the end crystals.
TNT or bed (optional) for the end crystals protected by iron bars or using them to damage the dragon(especially the beds in correct position)
Water can also be used to climb up to the protected crystals or if you’re good enough MLG water bucket to the ground.
A pumpkin (optional, not recommended) to prevent endermen becoming hostile when looked at.
Enchanted armor with Protection IV and Mending at least.(Armor type is recommended to be netherite but diamond is enough if you are semi-good)
A netherite pickaxe with Efficiency IV or V and Unbreaking III and Mending if the player spawns underground.
Ender pearls to teleport from the void or to the main island if the player spawns on a platform floating above the void.
Splash potions of Healing, Regeneration, Swiftness Strength (optional), Golden Apples (preferably enchanted ones), and Potion of Slow Falling (most important).
Food (high saturation), such as beef or porkchops).
A shield (optional), can be used to block attacks from both the dragon and the enderman.
A totem of undying (optional, but highly recommended).