My comments got cut by a character limit, so I'll put them here.
Bad is their newest song so I added it for that reason. That and because it's one of the best things I've ever heard in my life and I am addicted to it.
The Chaser is one of their best-known and biggest songs.
Only Tears I picked because it's a personal favorite ballad that makes me mega emotional. There's no music video so I snagged a live version.
Nothing's Over is good if you like cuter songs, and it's a good song to cheer you up.
Love Letter is a personal favorite. There's no music video for this either.
BTD (Before the Dawn) is well known for the dance more than the song. When you get to a certain part you will (hopefully) see why.
Destiny I picked as it holds a special spot since it was the first song of theirs I saw at their concert in 2013 so it's kind of an auto-pick.
Honestly they have SO many other good songs too, like Back, Last Romeo, Be Mine, etc. It was hard to narrow it down lol