Well now I have some rainbow to show a bit. Why not? Pretty pale compare to most people though.
On Nutaku: No rainbow from legit pull

Fritillaria: From step up gacha, get her from random rainbow pull.
Anemone: From 6000NG picked your rainbow deal. Stupid, I know. This is before I visit this forum after all.
Chrstmas Rose: From Easter deal (1500NG I guess?)

On DMM:

Epidendrum (swimsuit): From premium ticket. (just like how you yolo with 5FG) My very first legit rainbow from pure luck.
Saffron: from 10+1 priority pull
Anemone: From starter deal, I like her in Nutaku so there's no way I will left her behind like that.
Apricot: From 5000DMM recent deal.
Dogwood: From D ticket. Beat the 7.5% odd and got rainbow instead of gold.