The shaman is a primitive priest that has enormous utility to any group. They also have strong solo capability, chiefly outdoors. Their most prized abilities include their strong statistic and resistance buffs along with their slows, which are more powerful than those of other classes.
Shadowknights are a strong hybrid between warriors and necromancers - they are sort of the flip side of paladins, focusing on debuffing enemies, doing damage and getting significant area of effect threat to do their job.
The ranger is a hybrid class that mixes the abilities of a warrior with that of a druid, while throwing in considerable skill with the bow. Many of their buffs are similar to those of druids, and they have a very powerful snare that they can use to boost their ability to kite with a bow.
The necromancer is the master of death magic, using their frightful undead pets and powerful disease-based damage-over-time spells to kill anything in their path. They’re one of the most powerful solo classes, but their damage is significant enough that they are desirable in groups.
Monks are a class essentially modeled after the heroes of kung-fu movies. They use either simple weapons or their fists and feet, and only wear leather armor. Some monks also use one handed bashing weapons, and in many cases it’s the best way to go for the amount of damage that they do.
Magicians are the most pet focused class in the game, having a variety of different ones that they can use in different situations, along with an array of strong elemental spells for direct damage.
The druid is easily the most powerful soloing class in the game, as they make use of movement speed increasing buffs like Spirit of the Wolf and area-of-effect snares. They have strong direct damage and damage-over-time capabilities as well, along with access to some unique buffs.
It’s rare in Everquest that any particular class be considered the “best” at a particular role with no argument about it, but the cleric is the exception. Clerics are indispensable for healing, and they are without a doubt the best class for the role in every category.