Here are some Arkham related community resources that i enjoy. This is in no way meant to be a full list, just some links that i myself frequent. For a more complete list of everything out there, check out the link collection on Hall of Arkham.
Podcasts
Mythos Busters – (Podcast) – (Discord)
Drawn to the Flame – (Podcast)
Miscatonic University Radio (Podcast)
Video/Stream
Optimal Play – (YouTube) – (Twitch)
The Whisperer in Darkness – (YouTube)
Quick Learner – (YouTube)
Written Content
Rite of Seeking – (Blog)
Beyond the Veil – (Blog)
Obscure Studies – (Blog)
Mysterious Chanting – (Blog)
3 Aces (and 7 other things) – (Blog)
Utility
ArkhamDB – (Site)
Hall of Arkham – (Site)