Argentina international Funes Mori arrived at Goodison Park in September 2015, with Roberto Martinez - who was Everton manager at the time - splashing out a reported £10 million ($13m) to sign him from River Plate.
A regular starter in his first season, Funes Mori slipped down the pecking order under Ronald Koeman before a knee problem restricted him to just four appearances in the 2017-18 campaign.
The 27-year-old, who missed out on Jorge Sampaoli's World Cup squad, has now signed for Villarreal, penning a four-year deal with the Liga club.
The Argentine's departure is sure to be just a small part of the shake-up at Goodison as new boss Marco Silva looks to make a positive start the 2018-19 season after a disappointing campaign last time out.
Having spent big last summer and largely failing to deliver, Toffees fans will be expecting a higher standard of football as the Portuguese trainer prepared to head into the new term.
Funes Mori made a total of 67 appearances for Everton across all competitions, scoring five goals.