I guess that one was a bit hard. I'll be more flexible for fun. Your gem of choice, if you can't decide, then Peridot.
I will do two!
And I choose Pearl!
Roselia for Rose
Clamperl because I needed a Pearl reference in there
Kirlia because Pearl’s fighting style is based on ballet
Espeon because of the stone on its forehead.
Pidgeot because it can fly at a speed of mach 2 (apparently) and Pearl is very quick.
Clefairy cause it came from Space!
Magnemite - Tech and metal
Swadloon - Because Peridot likes being by herself and is an angry little green fella too
Dwebble - I figure she’d meet it on the beach and be fascinated by it
Larvitar - It has a similar attitude
Excadrill - The Kindergarten
Porygon Z - The Tech