Many of the classes in EverQuest can effectively solo. Some classes can solo and earn experience more efficiently than others, simply based on spell selection.
Necromancers, druids, and rangers are able to engage mobs through kiting. This entails snaring mobs, then running and causing damage throgh spells or propelled missles (thrown daggers, bow and arrow) from a distance.
Shamen, necromancers, and druids may opt to use root-rotting (or root-and-rot) as a method for gaining experience. Wizards, bards, and druids also have the ability to quad kite, or "quad". This involves engaging four mobs at once, and casting area-of-effect (AoE) direct-damage or death-over-time spells and songs while running in tight circles.
With the advent of mercenaries, soloing has become a viable option for melee classes. The ability to hire a cleric or warrior significantly reduces the need to spend time in finding someone able and willing to hunt in a particular area.