tantive

This plugin allows background images to be set for all blocks. 
You can set CSS background-image, background-repeat, background-attachment, background-position-x, background-position-y, and background-size.

Tantive Set Background

Example block scaffolded with Create Block tool.

taniafi786

A small WordPress plugin allows you to automatically change the wallpaper(morning,evening) according to server daytime.
<ul>
<li>
get server time by using 
$Hour = date(‘G’);
</li>
<li>
for morning image/wallpaper : $Hour >= 5 && $Hour <= 18
</li>
<li>for evening image/wallpaper : $Hour >= 19 || $Hour <= 4 </li>
</ul>
**You can change the hour value and images

WallpaperChanger

A small WordPress plugin allows you to automatically change the wallpaper(morning,evening) according to server daytime.

Tantive Set Background vs WallpaperChanger