It's all about...
Obsession? Pha! No... ... ...?
Cough Syrup - Blaine
Fly/I Believe I Can Fly - Artie, Blaine, Rachel & Santana [New Directions]
What Doesn’t Kill You - Mercedes, Santana & Brittany [The Troubletones]
Here’s To Us - Rachel [New Directions]
Glad You Came - Sebastian [The Warblers]
Stand - Sebastian [The Warblers]
[Zip File - With proper covers & tags]
Loveshack - Performed by Mercedes Jones, Kurt Hummel, and Blaine Anderson
Cherish/Cherish - Performed by Quinn Fabray and Mercedes Jones
I Will Always Love You - Performed by Mercedes Jones
Home - Performed by Rory Flanagan
Let Me Love You - Performed by Artie Abrams
L-O-V-E - Performed by Tina Cohen-Chang and Mike Chang
Stereo Hearts - Performed by Mercedes Jones, Sam Evans, and Joe Hart
You’re The Top - Performed by Hiram and Leroy Berry
I tried the whole chronological order thing, but that may or may not have happened. But this is every version of teenage dream (excluding glee live). These are among my favorite videos from the many times he has sung this song.
If I forgot any, let me know so I can add them :)