Some of the tools I use...
GM and player advice, reviews, etc. videos:
Dungeon Dudes
https://www.youtube.com/channel/UCQD..._6P1eBIfkTkC-w
Web DM
https://www.youtube.com/channel/UC7X...gaPzGyGbKk8GaQ
WASD20
https://www.youtube.com/channel/UCQO...TzH9dlThm8hbwQ
Adventure Lookup:
https://adventurelookup.com/adventures/
Map creation:
https://www.dungeonfog.com/
Mike Schley's maps:
https://mikeschley.com/
Stuff from Patreon (mostly maps, but some adventures and stuff, too):
https://www.patreon.com/maphammer
https://www.patreon.com/elventower
https://www.patreon.com/2minutetabletop
https://www.patreon.com/dynamicdungeons (mostly video/animated maps, but he provides static image versions also)
Campaign guides from Power Score:
https://thecampaign20xx.blogspot.com/