memrise (you can make your own course and add words that u want to learn and practice them) , talktomeinkorean (they also have books and they're so helpful), and howtostudykorean (it can give u a headache but it teach u a lot)
Fluent in 3 months is helpful although you have to pay. for free ones do NOT use Duolingo. I recommend LingoDeer which focuses on Asian languages as well as others. And drops that what I used and now I speak Korean, French, and I'm learning Chinese.