18-20 is a good time to go to Blightfire Moors (Crescent Reach stone). I start with the rats and snakes at the zone in, then on to the lockjaws and turtles at the pond, then the treants, and then to the white rats in the north of the zone from levels 25-35.
There's a quest you can do in Blightfire Moors in the same area as the white rats: http://everquest.allakhazam.com/db/quest.html?quest=3896 It takes just a few minutes to get started but the first steps summon a bunch of skeletons in one area that keep respawning for quite a while. If you kill them all and want more you can repeat it.. The gnarl thorns you need to kill to get it started are southwest of the quest giver, just inside the crater past the fog. When you give him the bark he'll walk to the center of the circle and light a fire. Shortly after, the skeletons spawn. Gubjak the Lost is located here: https://eq.magelo.com/npc/94472
At 20 be sure to do the repeatable quest Hatching a Plan. The quest giver is a high elf by the large bank in pok. Very nice xp.
For a TLP server after Paludal I would highly suggest Tower of Frozen Shadow in Iceclad Ocean. You can easily go from 20-45 there. Once a floor gets too easy just go up a level.
Unrest Basement is a pretty solid spot through level 30. It is way out of the way, but goblins in the basement in Highhold Keep is also excellent. The lower goblins will be deep red however. Super fast respawns though! TOFS is also excellent as suggested and offers leveling options for a long time. An alternative is also Crystal Caverns, there are three caves of generally similar difficulty that work through level 40 or so. Low teens may be a bit difficult however except for maybe the orcs. Zone is a one-way zone though. Once you zone in, there is only one way out via zoneline and it is across the zone. An underrated spot are the mosquitos in hidden Echo caverns (just before the water). They quad, but not for much damage. Due to the proximity of nexus, snagging a damage shield will help them basically suicide on you quickly and you just need to chase to finish them off. You can pull the little alien dudes to pass the time between respawns.
As others have mentioned; head on over to "Blightfire Moors" or to "Estate of Unrest (basement)" Unrest is good until level 33-35, then you can run on over to Dulak's Harbor until Level 46
Not sure what the level is, but I always loved Highhold Keep basement killing the goblins there.(Level 20-25 starting?) Several levels deep, and you should be good to around 30 or 35. Bank is close and vendors to sell the loot to.
