You can head to Erud's Crossing or North Karana at 15 to hunt wisps. Turn the Greater Lightstones in to the Gypsies in NK for really good xp at your level (about 2 blues per turn in) and then you can sell the item they give you back to them for about 9 or 10 plat each. In Erud's Crossing you can also kill madmen for a very low chance at a resist earring that sells well to vendors, but the magic resist one will sell very well in the tunnel. If you choose NK instead you can kill spiders and lions as well for silks and pelts which sell well to people working on crafting.
Low 20s I went to EK to kill spiders at the ramp to highpass. The spiders can drop up to 10 silks each and it's a good spot to solo or duo. Lots of spiders to go around and they aren't social. Orcs and gnolls in highpass are decent too at this level with good items from the named mobs that sell for a bit in the tunnel. Another good option is Upper Guk which honestly you can stay in Guk until you're in your 50s which is great if your shaman is a Troll or Ogre since it's close to your spells.
You could try going to Kurn's tower for some good drops at your level and then over to Warsliks Wood around 24 or so and hunt forest giants through root rotting. They drop items that can vendor for 45-65pp plus a very small chance at Forest Loops which sell in the tunnel for about 500pp each.
From the wiki:
Per Level Hunting Guide
A Treasure Hunting Guide