Allison and the Black Mamba remembered to fuel up while hitting the Oscar after-party scene hard ... with Oscar in hand, of course. They were at the Vanity Fair bash in Bev Hills and were joined by a slew of celebs.

The "Key & Peele" duo was there ... as was Oscar winner Frances McDormand, Drake, Halle Berry, Emily Ratajkowski and many more.

The famed Chateau Marmont on the Sunset Strip was also celeb central. Mary J. Blige, Salma Hayek, Tiffany Haddish, Amber Heard, Elon Musk and Anthony Anderson were all there. Cool of Nick Jonas to make his way over to the fans. Not cool of our camera guy to ask Stevie Wonder if he watched the Oscars. Habits, ya know.