i have been looking arround, and found never seen (by me) before tagz, like, %_filesize% %__bitrate_nominal% %__samplerate% %__extrainfo% %__bitrate% %__codec%, etc ... so, is there a list of all the tagz?

These tags are derived from the technical info you can find at the right side of the File Info dialog. To access them, just add two underscores in front of the identifier, similar to your examples. Some fields are only available for certain file formats, e.g. %__bitrate_nominal% just for Ogg Vorbis files.

thnks