Generated by SassMeister.com, the Sass playground.

SassMeister-input.scss

$body-blocks: p ul ol dl table pre blockquote figure img;
$heading-blocks: h1 h2 h3 h4 h5 h6;

@function proc($list) {
    $arr: unquote("#{nth($list, 1)} + &");
    @for $n from 2 through length($list) {
        $arr: append($arr, unquote(", #{nth($list,$n)} + &"));    
    }
    @return $arr;
}

.test {
    value: proc($body-blocks);
}

h1 {
    margin-bottom: 1em;
    p + & {
        margin-bottom: 0;    
    }
    #{proc($body-blocks)} {
        padding: 10px;    
    }
}
@mixin self-adjacent { & + & { @content; } }

@mixin adjacent($list:()) {
    @if $list == () {
        & + & { @content; }
    } @else {
        $arr: unquote("#{nth($list, 1)} + &");
        @for $n from 2 through length($list) {
            $arr: append($arr, unquote(", #{nth($list,$n)} + &"));    
        }
        #{$arr} { @content; }
    }
}

.test {
    @include adjacent() {
        color: blue;    
    }
    @include adjacent($body-blocks) {
        color: green;    
    }
}

SassMeister-output.css

.test {
  value: p + & , ul + & , ol + & , dl + & , table + & , pre + & , blockquote + & , figure + & , img + &;
}

h1 {
  margin-bottom: 1em;
}
p + h1 {
  margin-bottom: 0;
}
p + h1, ul + h1, ol + h1, dl + h1, table + h1, pre + h1, blockquote + h1, figure + h1, img + h1 {
  padding: 10px;
}

.test + .test {
  color: blue;
}
p + .test, ul + .test, ol + .test, dl + .test, table + .test, pre + .test, blockquote + .test, figure + .test, img + .test {
  color: green;
}