SHIMMER Women Athletes (2012-present)
Sylvia first appeared for SHIMMER Women Athletes on October 27, 2012 during the taping of Volume 49; teaming with Kira in a victorious outing against Angie Skye and Nikki St. John in a dark match. The following day, Thunderkitty teamed with Christina Von Eerie in a losing effort to Skye and Miss Natural in a dark match at SHIMMER Vol. 51.
Thunderkitty's first match on the main card was on April 13, 2013, when she was defeated by Allysin Kay at Volume 55. She would gain a victory over Sassy Stephie at Volume 57 the next day, despite attempted interference from Mademoiselle Rachelle. At Volume 58 on October 19, Thunderkitty was defeated by Portia Perez, who later took possession of Thunderkitty's robe after the match ended, but she would defeat Miss Natural later that same day at Volume 59. The next day, Thunderkitty lost to Saraya Knight at Volume 60 and defeated Taylor Made at Volume 61. At Volume 62 in New Orleans on April 5, 2014, Thunderkitty was defeated by Nikki Storm.
SHINE Wrestling (2014-2016)
Thunderkitty made her Shine Wrestling debut on August 22, 2014 and defeated Justine Silver in singles action at SHINE 21. Later in the event, Thunderkitty interfered in the SHINE Tag Team Championship match between The Lucha Sisters and Legendary by hitting Leva Bates with one of the title belts and allowing Legendary to retain the titles, establishing herself as a villain in the process. Thunderkitty was defeated by La Rosa Negra at SHINE 22 on October 10, but she would defeat Leah Von Dutch at SHINE 23 on December 5. Later in that same evening, Thunderkitty appeared and cost The Kimber Bombs in their SHINE Tag Team Championship match against Legendary.