The three players all leave the club after their contracts expired, as Villa let go of £12 million worth of talent.
Former England striker Heskey spent three years at Villa Park following his £3.5m move from Wigan Athletic, and went on to make 113 appearances for the Birmingham club.
However, the 34-year-old only managed 15 goals in that period, and has only found the net twice since the start of 2011.
Cuellar arrived at Villa from Rangers for £7.8m in 2007. His departure was widely expected, with the versatile defender getting an emotional send-off from the travelling fans at Carrow Road after Villa lost 2-0 at Norwich City on the final day of the season.
The Spaniard has already stated his desire to remain in England next season as he searches for a new club.
American keeper Guzan, a £600,000 buy, spent his four years at the club as an understudy, firstly to compatriot Brad Friedel and then to Shay Given.
Academy players Ebby Nelson Addy, Connor Taylor, Charlie Ward, Reece Caira, Richard Bryan, Matthew Coton, Darious Darkin and Seb Jenkins have also been released.