No idea how old you are, so I don't know what you consider "old" but here's a good variety

Usher - Confessions

Prince - too many good ones, but maybe Purple Rain

Boyz II Men - II

Marvin Gaye - Let's Get It On

The-Dream - Love/Hate

The Weeknd - After Hours

All For One - All-For-One

Rick James - Street Songs

Brian McKnight - Anytime

Mariah Carey - Daydream

Alicia Keys - Diary of Alicia Keys

TLC - CrazySexyCool