Best:
I just like the Cyan colors on Sceptile
The light blue on Nidoking
The rather calm Purple tone on Lapras
And the gold Cobra just looks awesome
Worst:
The worst ones is in general color palettes
Black and Red is too overrated in my opinion (Gonna prepare my flame shields for saying Shiny Char is worst)
Blue to Purple is just making them look worse, Kyogre is the same like Swampert in that way
Puke Green, it's just ehh