I agree with a lot of /u/Narahae's list. However some changes here and there to form my list:

– Drunken Tiger (Tiger JK in particular)

– Garion (MC Meta in particular)

– Dynamic Duo

– Outsider

– Vasco

– Dok2

– Epik High

– Swings

– E Sens

– Keith Ape

A lot of OG's from the Korean hip hop scene feature in my list, especially because they're all still active in the hip hop scene.

Tiger JK and MC Meta are the godfathers of Korean hip hop, soon followed by Dynamic Duo.

Even though Outsider's popularity isn't what it used to be he remains to have a huge impact in korean culture, especially noraebang culture (you can't go to karaoke without singing an outsider song).

Vasco, Dok2 have also been around for a very, very long time but yet they still put out contemporary music and are able to stay hip after 10+ years.

Epik High have created their own brand in korean hip hop and have certainly helped hip hop getting more mainstream in Korea.

Swings has been around for a while and has really turned the hip hop scene upside down with heavy influences from the US he's shown Korea a new style of hip hop.

I picked E Sens instead of the hip hop duo Supreme Team because E Sens has had more impact than Simon Dominic and I feel like even though Supreme Team had their share of popular songs, they always felt like a gimmick from amoeba to me. Also E Sens was the main reason for the diss war a few years ago. Which sparked international attention.

Keith Ape, although a newer rapper he's had more impact on the korean hip hop scene than any other artist in this list. He represents the future of korean hip hop and how the world views korean hip hop.

A few of my honorable mentions would go to:

– Paloalto: Starting up Hi-Lite, has been popular for a very long time

– MC Sniper: Old school hip hopper who works with a lot of new rappers these days.

I'm probably forgetting a ton, but this is all I got for the moment!