Novels finished before latest anime

https://en.wikipedia.org/wiki/Arashi_no_Yoru_ni - last novel ended 2005, anime in 2012.

https://en.wikipedia.org/wiki/Subete_ga_F_ni_Naru - novel ended 1996, anime 2015; untranslated VN.

https://en.wikipedia.org/wiki/Beyond_the_Boundary - novel ended December 18, 2013, same as anime, but latest film was in 2015.

https://en.wikipedia.org/wiki/Run_with_the_Wind - novel ended in 2006, manga 2009, anime 2019, so likely finished if fully adapted.