Twin/doppelganger drama

 kwoon:

Where FL or ML is a twin or doppelganger and takes over their counterpart's identity

• +1 The Crowned Clown - Doppelgänger
• +1 Who Are You: School 2015 - Twins
• +1 Are You Human Too? - Human and robot
• +1 The Masked Lover - Twins
• +1 Ugly Beauty - Twins
• The King's Affection - Twins
• You're Beautiful - Twins
• High School King of Savvy - Brothers

Main character's soul enters another person's body and takes over the body's identity:

• +1 The Eternal Love
• Mr. Queen
• The Legends
• The Untamed
• The Romance of Tiger and Rose
• Moon Lovers: Scarlet Heart Ryeo

Second Husband - it is still airing right now, the FL pretends to be an investor "Sharon Park" in the second half of the drama to get revenge on the FL villain and uncover the truth over her being framed for a murder. The episode count looks high (120 eps) but it is addicting so far every episode ends in a cliffhanger that makes you want to watch more of it.