I had this idea and it just seemed appropriate for this theme, so I'm entering.
Zekrom and Reshiram playing chess. The chess pieces are as follows:
Pawn - Pawniard
Bishop - Bisharp
Knight - Braviary (White)/Mandibuzz (Black)
Rook - Lilligant (White)/Whimsicott (Black)
King - Reuniclus (White)/Gothithelle (Black)
Queen - Zekrom (White)/Reshiram (Black)
The details may be hard to see since I had to shrink it down to fit the rules of the contest. I'll upload a larger version later.