The Vampire Diaries franchise often gave new actors the opportunity to show off their range, which frequently resulted in them gaining widespread attention and featuring in other supernatural franchises, such as Once Upon a Time. Between The Vampire Diaries and its spinoffs, The Originals and Legacies, the franchise had 331 episodes, which meant that actors could easily find a role that they were well suited for, whether that meant serving as main characters, love interests, or guest stars. In addition to a line on their resume, The Vampire Diaries actors gained experience working with various props and effects to fit the supernatural setting, which was beneficial in their future careers.

https://screenrant.com/vampire-diaries-actors-roles-once-upon-time-characters/