Basically, these are the outfits Taemin wore in JITM 2;
Alexander Wang's black suit pants
Dsquarded's tight fitted black shirt
The ankle boots (WHICH I FUCKING LOVE SO MUCH) from Givency
Burberry Prorsum's belt
Björn Borg's briefcase
As for Key's top:
Noir&Blanc's cottony black blazer.
And the diamond I mentioned in chapter 2:
one of the most expensive jewelries in the world.