Most gnomes don’t think much about the afterlife. Attempts to contact and study those that have passed on generally yields inconclusive results, with one exception: Ghosts.
Ghost are real, as is the shadowlands. They can be interacted with and examined through sciomancy. At one time this lead to the formation of a group of gnomes who believed becoming a ghost was the only hope of an afterlife. (If not the ONLY hope, at least it was preferable to reintegration with the environment or oblivion.) These gnomes became Sciomancers of the highest caliber. Able to contact and control the spirits of the dead, and even enter the shadowlands.
While Gnomeregan had no official laws against Necromancy or Shadow magic at the time, the group was still looked down upon and outcast. Most of these Scimomancers went north to Lordaeron to study at the school that became Scholomance, and were lost to the scourge.