I request this plugin because I think it would benefit a lot of developers and I think is relatively easy to do.
The main idea is to separate the icon in two files differents layers:
* Background
* Sygil
My idea is: What if we make the sygils (the white icon part) transparent so we can get literally any imaginable combination with only a few icons. As we mainly only need the skills, items, weapons and armors icons, I think we can achieve the background color settings via notetag, something like:
<icon background: 2>
and use the proper icon sygil as the one usually stored in the database.
An example image. Sorry about my explanation. My english is very rusted.
BTW, @WaywardMartian did an amazing job getting the MZ's RTP icons backgrounds. Kudos and credits by the background used in the example:
Wayward's MZ Resources (Latest 201015: Trapdoors)