Great!
I thought there was no way to store tags that are not vanilla in entities, so thank you for this resource, it'll be really useful to get rid of some databases ;D

I love this, because it taught me how to make my own functions using Skript. :) I pretty much recoded the entire thing for own use and just learned so much from this, thank you.

I wanna make a recommendation however! Your KeyTagValues are using a "=" between the name of the tag value and the actual value. While that is going to work fine internally, it does not work if intended to use with minecraft vanilla targeters (for example @e[type=chicken,tag=points=1]). The example should make clear why that is an issue that vanilla targeters can't digest ^^

I use ":" instead of "=" in my version which do work and i'm sure many others would work, too. Just a heads up. :)

Cheers

Your script is very very optimized, thanks for this.
I love you ! Because the Skellett nametag support is buggy