A unicorn is a tech company valued at over $1B. The Unicorn Club includes companies currently valued at over $1B, and those that have successfully completed a $1B+ exit. To learn more about the different types of unicorns, check out 'What is a unicorn?'.
If you want to be ahead of the unicorn curve, check out this query of potential future unicorns, or see new unicorns created by year in different geographies.