Dragon Eggs

Get 8 Dragon Eggs, and you can exchange them for: Everyone gains 2 levels, a Might Shield, a Might Bow, or have the Dragon use 3 of every type of potion on your team. I always get the Might Bow then 2 Might Shields.

First set of Eggs:

Old Cave, 2nd floor
Ghost Cave
Red Tower
Cave west of Odel
Grief Tower
Linze
Gayas Cave
Ullup Island Cave

Second set of Eggs:

Alekia Castle
Belgen
Cave west of Linze
Cave southwest of Belgen
Elba Island Cave
Underwater near Soshette
Oil Cave
Northwest Tower

Third set of Eggs:

Cave to Guy's House
Sheran Castle
Lyden
Old Cave, 7th Floor
East of Herat Cave
North Cave
Southwest Cave
Glasdar Tower