In the twenties I went to a number of different places, I could never settle down in one spot, along with being a big quester myself, it made me a very slow leveller.
This is just in general for a twenties character, since you have named many characters.
One of the very nice places I discovered was Gargoyle Island in the Ocean of Tears. Not only were the mobs on that island incredibly easy, but it was also very good loot. They drop Gargoyle Eyes (uncommon and stackable) and research items. The eyes sell to merchants for ~9pp each with about 85 charisma.
You might also want to try goblins in the Highkeep basement, highkeep has one of the best zems in the game. Plus (iirc) fine steel and bronze armor.
Aviaks in Lake Rathe are pretty nice xp, pull to arena zoneline. They drop fine steel and research.
Lake of Ill Omen, despite being one of the only two zones in the game that has a negative zone experience modifier (The Grey being the other) was at one time a very popular zone because of how easy the mobs were. It is less crowded now, which means if you can solo, or stand to wait a little bit to find a group, you can get some nice xp here.
Overthere in Kunark is a good hunting zone all the way up into the 40's. The side you would want to hunt in would be the area on the coast. This was once termed part of "The Kunark Express" because of how fast the xp came in.
Once into the twenties, you can also do LDoN adventures, which yield a ton of xp, cash, and loot. I would recommend Mistmoore if you choose to do so.