skiplists form the basis of in-memory tables used by LSM trees, which are themselves the basis of most modern DBs (written post 2005).

Skiplists have some nice properties - the code is fairly short and easy to understand, for one. Qt's QMap used to be skip list based, here's the rationale given for it: https://doc.qt.io/archives/qq/qq19-containers.html#associati...