Concept Artwork (possible spoilers):

sketch of White Chimera (Ronso)
White Moomba
White Ronso and Mako
White Chimera sketches
"Inside Mt. Gagazet" - White Ronso, Mako, Kumog, Mew
Kumog and Mew
"Swimming Lesson" - White Zora and Pillea
Zidane and Moomba White Moomba and the GF Hunters

Other Artists' Work (thanks!):

Iifa Girl by maggiekarp
Iifa Tree by maggiekarp
Galbadia Garden SID cards by Seris: Daniel, Doug, Marie