Resources
The official D&D site from Wizards of the Coast (WotC). You can buy books, digital dice, and even get some basic/generic information on the for free.
Find it here:
Cost: some free, some paid, subscription
Plenty of gaming shows, but also the home of Dimension20 and Brennan Lee Mulligan and the series of adventures that is a nice and fun foray into D&D 5th edition.
Check'em out:
https://www.dropout.tv/dimension-20
Cost: subscription*
*You can find episodes on YouTube if you prefer
Roll20 is a virtual tabletop (VTT) website that helps run digital campaigns. They have a lot of items here, but one nifty thing is that you can buy some of the D&D modules. When you purchase them here, the book is available through their interface, but they also have the books' maps and tokens as well.
Look at this:
Cost: some free, some paid, subscription
D&D Speak has a lot of entries that can help provide you with thoughts and ideas. Need help thinking of a name or a trait?
Visit here:
Cost: some free, shop, Patreon
Need a name for something but you're drawing a blank. Try the Fantasy Name Generator website. I guess technically it's Generators with an S, but back when I first used it, it had only a few.
Bonus: they plant trees!
Visit here:
https://www.fantasynamegenerators.com/
Cost: free
Ever wanted to design you a character for visual reference? Hero Forge makes that easy and you can even order your character after. You can even buy the print file and print yourself if you want.
Visit here:
Cost: free design, some paid , subscription
You can build maps here, and some of them are very, very good. Give it a look and see if there's something there you can enjoy
Visit here:
Cost: some free, subscription
The Order of the Stick. A silly comic that uses D&D and is pretty funny. It makes fun of itself and its "players" realize they're in a game.
Visit here:
https://www.giantitp.com/comics/oots0001.htm
Cost: free
More Resources
Of course there's more, but come on, I gave you eight things already. I'm sure you can Google and find more.
Hint: Use Google and add site:reddit.com to your search to limit Google to showing you only results from Reddit.