Books! Visit your library and see what books are available for free. That's one thing that I'm doing; just working through every single library book on poker available.
Podcasts! Poker on the Mind, Heads Up Poker, Dat Poker Podcast, The Mindset Advantage Podcast, Under the Gun, Red Chip, The Poker Guys, Carrot Corner, Smart Poker Study, Ante Up, Full Contact Poker, Weekly Poker Hand, Two Plus Two, Poker Central Podcast Network, Poker Life Podcast, Top Pair, Tournament Poker Edge, Rec Poker.
Videos! YouTube and
Twitch.
Forums! Here, Reddit, RunItOnce.
Study Groups! I'm thinking of forming one on Snapchat, so Inbox me if interested.