Non-canonical Namespaces
Namespaces that are either out of use, or contain no information relevant to PTR. In general, don't push these namespaces to PTR.
Uploader
uploader is a namespace primary used by the Reddit parser to denote which user uploaded a work to...
Copyright
The copyright: namespace, while used on danbooru and e621, is not recognized on PTR. Use series: ...
Pool
Say you have a group of images that you want to represent as being "together" in some way. Either...