This is not intended to be comprehensive or authoritative, just free online resources I've found valuable while learning more about Erlang.
- 0xAX's list of Erlang bookmarks
- Federico Carrone, Erlang Spawned Shelter
- Ivan Uemlianin's list of resources on various BEAM languages
- David Robakowski's curated list of awesome Erlang libraries, resources and shiny things
- Julius Beckmann's curated list of amazingly awesome Elixir and Erlang libraries, resources and shiny things