<?php register_admin_color_schemes(); ?>

$current_color = get_user_option( 'admin_color' );

<?php
    $admin_colors;
    add_action('admin_head', function(){global $_wp_admin_css_colors; $admin_colors = $_wp_admin_css_colors;});
?>

$admin_colors[get_user_option('admin_color')]['colors']; // array(0 => #222, 1 => #333, 2 => #0074a2, 3 => #2ea2cc)

$admin_colors = Array
(
    [fresh] => stdClass Object
    (
        [name] => Default
        [url] => https://example.com/wordpress/wp-admin/css/colors.min.css
        [colors] => Array
        (
            [0] => #222
            [1] => #333
            [2] => #0074a2
            [3] => #2ea2cc
        )
        [icon_colors] => Array
        (
            [base] => #999
            [focus] => #2ea2cc
            [current] => #fff
        )
    )
)

get_user_option( 'admin_color', get_current_user_id() );

<?php

/**
 * Set the default admin color scheme for WordPress user.
 */
add_filter('get_user_option_admin_color', 'set_default_admin_color');
function set_default_admin_color()
{

    // set new default admin color scheme
    $result = 'midnight';

    // return the new default color
    return $result;

}

/**
 * Get the current admin color scheme from WordPress user.
 */
add_filter('get_user_option_admin_color', 'get_current_admin_color');
function get_current_admin_color()
{

    global $_wp_admin_css_colors;

    // get current admin color scheme name
    $current_color_scheme = $result;

    // get all available colors from scheme name
    $colors = $_wp_admin_css_colors[$current_color_scheme];

    // now you can use this colors or store it
    // var_dump($colors);

    // important: we should return the default color scheme
    return $result;

 }

/**
 * Get all available admin colors schemes from WordPress user.
 */
add_filter('get_user_option_admin_color', 'get_all_admin_colors');
function get_all_admin_colors()
{

    global $_wp_admin_css_colors;

    // get all available color schemes
    $colors = $_wp_admin_css_colors;

    // now you can use this color schemes or store it
    // var_dump($colors);

    // important: we should return the default color scheme
    return $result;

}