He founded the symphonic metal band Apocalypse with Mark Jansen in 1995, which later changed its name to After Forever.

After recording all guitars for the album Rise of the Warrior by Anna Phoebe, he began a project called HDK, which is signed to Season of Mist; HDK's debut album, System Overload, was released on 23 February 2009.

Resulting from his partnership with Amanda Somerville on HDK and Kiske/Somerville, Sander became one of the main members of Amanda's self heavy metal-oriented project called Trillium, which first album Alloy was released in fall 2011 by the record company Frontiers Records.

Between 2015 and 2019, Gommans joined forces with Scott Wenmakers (teacher and illustrator) and Menno Kappe (Graviton Music Services)[3] to work on "Enter the Metal Realm", the first chapter of Magic-O-Metal, a heavy/power metal musical project for children.

On 15 December 2021, Gommans released a song called "Lords of Power Theme".