I think it's ok to begin with some Series on this list. Eternal Monarch and Lonely and Great God were some of my first ones, and it was alright. They have become some of my favorite

Goblin us one of best drama I have ever watched. Gong yoo is the most talented actor .and a hadsome actor I have watched this drama more than 10 times just loved the story and the caste of all the characters was just amazing Lee Dong-wook was great in drama.