The best chess resources I know of

Sites

• Lichess — the best chess site, full stop. Open source, no paywall for any features, and better than chess.com for learning in every way. If you only click one link here, make it this one.
• Chessable - offers paid courses but there are plenty for free:
  • Smithy's Opening Fundamentals
  • Tactical Resources: Creative Attack & Defense
  • Basic Endgames
  • Basic Checkmate Patterns
• Free (and legal) chess books on Project Gutenberg — public-domain classics you can actually read without a subscription. Update: book quality is low/mid, and the site forces you to read online in a shitty UI. Plus they do their best to not allow PDF downloads.

YouTube

• St. Louis Chess Club — lectures without all the fluff
• John Bartholomew's Climbing the Rating Ladder playlist — calm, practical rated games as he climbs
• ChesswithAkeem — cringey "YouTube face" thumbnails and clickbait titles, but the live games with analysis have been super helpful for me

You can reach 2000 Elo without spending a cent on learning. Don't get suckered into a paid course or subscription if you're below 2000.