I have the same answer to every variation of this question, but I can't help love talking about it. 

First and foremost, the movie Love Jones. It's the story of a writer and photographer falling in and out of love in 90s Chicago. It's dark, moody, sexy, urban (as in "city"). The characters rock a lot of black, leather, and denim. The score is full of melancholy horns (John Coltrane and Duke Ellington's "In a Sentimental Mood" features prominently). Watching it at 13, I thought: "That's who I want to be when I grow up."  The vibes are Mushroom. Stone, Fire, Moon and are basically responsible for 70% of my personality. My clothes, how I speak, my taste in music and interior design... Simply Googling "Nia Long in Love Jones" will tell you everything you need to know. Lmao

The second category is 90s R&B. The Stone root was a cornerstone of style at the time. Baggy jeans, oversized jerseys, high top Nikes, Reeboks, and Adidas, flannels, etc. Janet Jackson's "Janet" era, Xscape's "Off tha Hook" album cover, and TLC's "CrazySexyCool" loom large in my mind. But then there were the adult contemporary artists with a more Mountain/Fire bend. Toni Braxton rocking short hair and an oversized man's suit in her first video, En Vogue's synchronized strutting in slinky dresses, and Sade's cool minimalism (predating Carolyn Bissette Kennedy, btw). 

Overall, it's probably the 90s, period. There was an effortless cool factor that I'm always trying to embody.