A SCSS function generating 100 classes from green to red.

greentored.scss

$i: 0;
$color: rgb(0, 255, 0);

@while $i < 100 {
  $i: $i + 1;
  .color-#{$i} {
    color: $color;
  }
  $color: adjust-color($color, $red: 2.55, $green: -2.55);
}