I have written my own skillet plugin. But every time when I update the addon I have to add the plugin in the TOC file.

Would it be possible to load all plugins located in the Skillet-Classic/Plugins folder automatically?
This would make it unnecessary to list them all in the TOC file.

Unfortunately, it is not possible for addons to selectively load other addons. However, plugins for Skillet-Classic don't have to reside in the Plugins folder or be included in the Skillet-Classic TOC file.

Here is an example, SkilletTSMPlugin-v1.0.zip, https://www.curseforge.com/wow/addons/skillettsmplugin.

The magic is ## Dependencies: Skillet in the TOC file. The namespace (which you are already using) and the register functions in ...\Skillet-Classic\SkilletPlugin.lua (there's an AddRecipeSorter function defined in ...\Skillet-Classic\UI\Sorting.lua. This should all be documented in ...\Skillet-Classic\ThirdPartyHooks.lua.

What does your plugin do?

Very nice! Excellent way to use both the prefix and suffix.

Thanks for your answer @b-morgan! That is very cool I didn't know that I can completely put my plugin outside of the skillet-classic folder.

What does your plugin do?
My Addon tracks the items, that I auction and that I have in the Inventory of my chars. The Skillet Plugin of my Addon shows the number of my existing items as Prefix before each item. With this I know what gems or glyphs I not have as auctions or in my inventory somewhere and can build the queue quickly to refill the AH with my stuff ;-). With the combination of the suffix of auctinator, I can see what Item I have not in the AH and what profit I would get for this Item.

You can find the Plugin code here: https://github.com/hogfather-wow/Skillet-Classic-Plugin-MeineAuctions
And the Addon code here: https://github.com/hogfather-wow/MeineAuctions