Other 80's Brat Pack teen films include:-
15) The Outsiders
16) Oxford Blues
The Brat Pack made a ton of other films together but I don't consider them to be teen films. I'll give them a quick mention if anyone is curious - St Elmo's Fire, Blue City, About Last Night..., Wisdom & Fresh Horses.
As well as making films together, they've starred in a lot of their own 80's teen flicks that aren't classed as Brat Pack films. I'll give a run-down of their individual films that I've seen but haven't previously mentioned.