While surfing I often save documents and files of all types. As time goes on accumulating so many files, and I have trouble ritrovalrli.
I tried the program TagSpaces that allows me to just tag the file with simplicity in order to facilitate further research. But this is a bit inconvenient as I have to open a separate program and is not integrated with Dolphin.

With Nepomuk in Dolphin can do more or less the same things, but do not find it as rich in features such as the ability to drag a tag to a file previously defined, create categories of tags, create colorful labels etc. ..
There are so many plug-ins to download for Dolphin and would like to know if there are to improve the management of tags in a manner more similar to what you can do with TagSpaces.
I have not found yet!

Tanks!!!

Can you please clarify what you are trying to achieve?
Also, which version of KDE are you using?

I use KDE 4.13 on Kubuntu 14.04
Above all I would like to create categories of tags, in order to tag my files faster with greater precision and even more clearly.

Thank you

You could try Baloo however it uses the same system of tagging Nepomuk did - it doesn't support the "categories of tags" you're after i'm afraid.