I suggest new soft green themes and wallpapers that match Linux Mint official website colours, Like OpenSUSE does. I have come across a theme called ENERGREEN on noobslab that matches these criteria. Wallpapers should have something like mint leaves and soft green colours. Cinnamon default theme should match Mint-X theme and should not be black and that to give a sense of visual harmony and perceptual continuation.
Linux Mint Mate/Cinnamon
+ Ultimate Edition