6. Lyft

Lyft launched in 2012 as a ride-sharing app. The idea morphed out of Zimride, a company founded by John Zimmer and Logan Green that offered carpooling for long-distance rides and campus car-sharing programs.

Fast forward to 2019 and Lyft is now a $13 billion company that's dabbling in electric scooters, bike share, and self-driving car technology. The 7-year-old startup went public earlier this year.