Attacking midfielder Davy was Everton’s second summer signing in 2017.
He arrived from Europa League finalists Ajax in a €27m move, penning a five-year deal.
A Netherlands international, he had served as captain at his former club, having been handed the armband ahead of the 2015/16 campaign, aged just 22.
In his final season at the Amsterdam Arena, Davy netted 16 goals, including two in the Europa League as Ajax went all the way to the final in Stockholm, only to suffer heartbreak against Manchester United.
He also displayed his creativity, contributing nine assists as Ajax finished second in the Eredivisie, just a point behind rivals Feyenoord.