KoreanClass101
Lots of podcasts and lesson transcripts for various Korean levels. Somewhat spammy marketing, but solid content which I’ve been using for years.
Pathway to Korean
Free beginner lessons online from Ohio State University.
K2nlearner
A new, robust site to learn natural Korean in the context of phrases. The site is run by my friend Jimmy and he posts useful phrases and slang.
Talk To Me In Korean
The ultimate Korean resource. If you aren’t using TTMIK, what are you doing? Just kidding. They have podcasts, free lessons, textbooks, videos, the whole shabang.