Luton have signed former Peterborough and Brighton striker Craig Mackail-Smith on a two-year deal.
Norwich City have completed the signing of goalkeeper Jake Kean following his release from Blackburn Rovers.
The 31-year-old joined the Seagulls after leaving Valencia in 2011 but has struggled with injuries throughout his two seasons at the club.
Fellow midfielder Gary Dicker and full-back Marcos Painter are also leaving at the end of their contracts.
The club have extended the contracts of skipper Gordon Greer, fellow defender Inigo Calderon, strikers Ashley Barnes and Will Hoskins and back-up goalkeeper Peter Brezovan by another year.
They have also offered new deals to centre-half Adam El-Abd and midfielder David Lopez.
Chairman Tony Bloom told the club's official website: "On behalf of Brighton & Hove Albion, I would like to thank Gary, Marcos and Vicente for their efforts on behalf of the club and wish them well in their future career."
Loanees Wayne Bridge, Dean Hammond and Matthew Upson have returned to their parent clubs.