Playground Kid gives access to aev_fild01 which is the main leveling room. See: Beginner's Guide (leveling guide).

The monsters in the room have drops that are used as ingredients for Pandora.

Item Monster
Eye of Dullahan
Eye of Dullahan Dullahan
Fabric Whisper
Hammer of Blacksmith
Hammer of Blacksmith Dokebi
Soft Silk
Soft Silk Evil Nymph/Wicked Nymph
Star Dust
Star Dust Whisper

Other monsters include Giant Hornet, Leib Olmai, Side Winder, Arc Angeling, Myst Case, and Carat.