From the Dark
Gnomes have always been a curiosity to other races. Their ties to magic and the fey cause distrust, but their willingness to help other races helps to stave that off. It is rare for a gnome to be an enemy of the people. On the contrary, they have proven quite helpful in designing some of the grand architecture of the world. Magic is woven into many places and it is frequently gnomes that are responsible.
The gnomes that don’t rise to such heights typically find themselves as tinkerers of some kind, or occasionally entertainers. The entertainers team up with others such as gypsies or halflings and provide them with magic they may not have had. The tinkerers usually keep to themselves, commonly employing ratfolk as assistants. They sell or trade their products and are mainly interested in the craft itself, not the results.
Gnomes could have any number of reasons to go into the mists. They may want to see some of the greatest feats of gnome architecture, now lost in the mists. They may have lost friends inside. Or they may even fancy themselves a small but noble champion of the realms.