I use two color themes. One for my daily work, and one as a fallback.
As a main theme, I use the Nord Theme. I try to apply this theme system wide, so I use it also with vim.
There is a git repo for the plugin, comming from Arctic Ice Studio.
It contains a nord.vim file, which contains some color definitions.
Plug 'arcticicestudio/nord-vim'
As a fallback I use jellybeans
This theme works even well with an non 256 color terminal.
Plug 'nanotech/jellybeans.vim'