I was talking with one of my Korean friends about songs even non-Kpop fans know and she confirmed this list lol, there might be more but this is what we came up with!
1. Wonder Girls - Tell Me
Every Korean ages under 35 years old (and honestly, probably even older people too!) knows some part of this dance or can at least recognize it immediately. This dance took over Korea waaay before Gangnam Style.
2. HOT - Happiness
I first knew this from the Super Junior version, but most Koreans would recognize the HOT version first :)
3. In Soonee - I Have A Dream
This is a ballad that is used over and over and over again. Its a really popular song for noraebang, and just covers in general. Listen to the chorus, you might have already heard it before!
4. SNSD - Gee
This is pretty obvious! I think most of the world actually knows this song by now :)
5. Bi - Rainism
This song was insaaaanely popular when it came out and pretty much any boy band at the time did a cover of it. Especially the "I'm gonna be a bad boy part" - everyone knows it!