I've been worldbuilding for as long as I can remember. I probably have a dozen fully thought-out worlds and a hundred half-baked ones. I even wrote a speech about it (and won a contest for it) :p
stoneworks worldbuilding. - Great guides on geography and his minecraft worldbuilding server is good for inspiration.
tale foundary. - Talks about these obscure (at least to me) books that are great for inspiration.
hello future me. - Awesome long-form video essays about writing and worldbuilding that are perfect background sounds for work.
brookes eggleston - character design forge - Art tips for cool character design. Great for fantasy races and art tips in general.
runesmith - Mostly comedic D&D stuff but great for inspiration for other works as well.
artifexian - Uses real science to help build fictional worlds.
james tullos - Critiques fantasy novels for their worldbuilding and has a worldbuilding guide series too.
wasd20 - A D&D mapmaker and a major inspiration for my love of fantasy cartography.
mariah pattie worldbuilding - Talks about her worldbuilding in depth and she loves fashion in particular and I think thats a part of worldbuilding that is often overlooked.
worldbuilding notes - Short videos with unique worldbuilding snippets that never fail to inspire me every time.
matthew colville - D&D guides but his worldbuilding streams helped me a lot, especially for pantheon building.
shadiversity - Great inspiration for medieval fantasy and has some ttrpg campaign and worldbuilding guides.
weltengeist - Detailed videos about their world.
aquilifer worldbuilding - Detailed videos about their world and their thumbnails are cool.
leo leonis - Fantastic mapmaker and talks about their world in detail.
nakari speardane - Talks about her world in detail and I love her art style.
four crows - Great ideas in his worldbuilding that inspires me a lot.
joriam ramos - Worldbuilding and writing exercises in every video.
just in time worlds - Goes in depth about different aspects of worldbuilding.
terrible writing advice - Goes into difefrentt writing tropes and calls them out.
the templin insitute - Talks about different worldbuilding, mostly scifi, and has guides as well.
camelworks - Elder Scrolls and Fallout lore, useful for inspiration.
fudgemuppet - A lot of Elder Scrolls and some Fallout too, has great podcasts about it.
team darkside's mh lore - Examines monsters in Monster Hunter trhough the perspective of an actual in-character hunter, really good for inspiration.
keenan taylor's tales of kaimere - Talks about their worldbuilding that involves prehistoric creatures, dinosaurs, sabertooths, and speculative fiction oh my.