Based on the awesome job of [email protected] documenting the stuff and applying it to solarized, I tried to do the same with my vim favorite theme: everforest. It's far from perfect (I'm not at all a designer), feel free to improve your way (and share updates in comments). The zinc theme is probably more refined because I use only this one, I tried to make slate match the palette but as I'm not using it it's more difficult.
A screenshot: 
{
"other": {
"white": "#FDF6E3",
"black": "#002b36"
},
"primary": {
"100": "#A7C080",
"900": "#8DA101"
},
"zinc": {
"50": "#D3C6AA",
"100": "#A7C080",
"200": "#DBBC7F",
"300": "#D3C6AA",
"400": "#D3C6AA",
"500": "#D3C6AA",
"600": "#4F585E",
"700": "#4F585E",
"800": "#425047",
"900": "#232A2E",
"925": "#2D353B",
"950": "#2D353B"
},
"slate": {
"25": "#FDF6E3",
"50": "#FDF6E3",
"100": "#EFEBD4",
"200": "#E0DCC7",
"300": "#E0DCC7",
"400": "#D3C6AA",
"500": "#5C6A72",
"600": "#5C6A72",
"700": "#5C6A72",
"800": "#5C6A72",
"900": "#8DA101",
"950": "#8DA101"
}
}