You can search these up and read on other websites (Like Czbooks) as they are not completely published on NU. 

Where the plot contains MC being switch at birth or at young age with someone. Stories here also include those of similar trope as the CENTER, such as someone being kidnapped/lost/died at a young age and the family took in someone else as a sort of "replacement".... more>>

Tier is base on when they are added in this list: with the higher number being the most recently added and 1 the oldest. 

Part 1: https://www.novelupdates.com/viewlist/30345/ <<less