[2][3] In August 2016, Seola, alongside group members Exy, Soobin, Eunseo, Cheng Xiao, Yeoreum, and Dayoung collaborated with label mates Monsta X to form the unit "Y-Teen".

Y-teen was a project unit group that promoted as CF models for KT’s phone fare service and would release EPs, music videos, and various entertainment content.

[4] In November 2017, Seola made her acting debut when she was cast for a supporting role in Naver TV's short web-drama Good Morning Double-Decker Bus.

[5] On May 2, 2018, Starship Entertainment and Fantagio collaborated to form a special four-member unit named WJMK, consisting of members of their respective girl groups WJSN and Weki Meki.

[10][11] In June 2019, Seola starred in Naver TV's web drama In-Out Sider as Jung So-min, an icon of students' first love, who has everything from appearance, personality, and studies to missing.