Weller was one of 12, under-17 players taken by the Suns in 2009 as part of their initial list build.
However, the 20-year-old from Tasmania struggled to nail down a spot in the back six, playing 32 games in his three seasons, including just four this year.
Gillbee, Patrick and Wilkinson were all part of the original 2011 squad, while West Australian Horsley was acquired at the end of the Suns' first season and had his 2013 cut short with a ruptured ACL.
Gold Coast has gradually been reducing its list from an original size of 48 in 2011 and must reduce it from 42 to 40 by the start of next season.
As well as the required three draftees, Gold Coast will welcome Jack Martin to its list next year, meaning they have just one more spot to vacate.
The Suns can do this via another delisting or trading.
General manager of football operations Marcus Ashcroft commended the players for their contribution to the Suns.
"The players leave knowing they played valuable roles in our clubs establishment and will always be welcome at the club in the future,” Ashcroft said.
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