Looking at it now, it's a bit cringe-worthy but when it first came out, it was the song! Many fans still love it despite the bright colors, mismatched outfits, and interesting hair choices. To this day, this is still a favorite of any VIPs and BlackJacks. This is also the song that introduced many people to 2NE1.

At this time Trouble Maker was considered the sexiest and most mysterious collaboration there was. They were one of the first to start the co-ed group trend and now we have groups like KARD that share the co-ed concept and fans everywhere love it.

Fun fact, The One was Taeyeon's vocal trainer when she was younger and here they are making an incredibly touching song together.

G-Dragon has always impressed with his powerful and meaningful lyrics and there's no better way to share that than with Lydia Paek's great voice to back up the rhythm and reggae vibe.

The Adam Couple, one of We Got Married's favorite couples, shocked all fans when they wrote and performed a song together. During this time they were the ultimate OTPs and this song just serves to prove although their love might not be real, the chemistry is.

A charismatic song for two very charismatic women. IU proves herself to be much more than just the Nation's Little Sister in this video but instead opts for a feminine chic look in a slim fitting suit. The collab is interesting because of the contrast of IU's innocence with Ga In's sexy vibe.

The queen of sexy pairs up with a young Zico to give us an amazing performance that every fan can watch over and over again.

What a surprise that now Jung Hoseok (J-Hope) is part of the biggest and fastest growing K-POP band ever. And it proves to show that even before his rise to fame he was always a talented rapper. Along with Jo Kwon's fierce sassy stage presence, this proves to be a powerful performance you can't take your eyes off.

At this time, Girls' Generation and Super Junior had an incredibly strong growing fanbase so it only made sense for them to do a collaboration and that was one of the best decisions that could happen during this era. The SMTOWN chemistry is on full display.

Incredibly intense and moving, this music video is hard to watch but also touching at the same time. The song shows the great contrast between Bang Yong Guk's raspy and deep voice with Yoseob's softer tone.