Inside the terraria community, my favorite youtuber is gameraiders101, because of his unique video ideas, and overall he's entertaining to watch.
Outside the teraria community, my favorites are:
Post plantera is my favorite because You have a ton of new weapons and armor to get before fighting golem. You can go to the dungeon, You can fight the full solar eclipse, You can fight the pumpkin and frost moon, You can fight the empress of light. It's really up to you. It's also nice because...