Mutag

Some common tags:

APIC --- Attached picture

COMM --- Comments

GEOB --- General encapsulated object

PRIV --- Private frame

TALB --- Album/Movie/Show title

TCOM --- Composer

TCON --- Content type

TIT1 --- Content group description

TIT2 --- Title/songname/content description

TPE1 --- Lead performer(s)/Soloist(s)

TPE2 --- Band/orchestra/accompaniment

TPUB --- Publisher

TRCK --- Track number/Position in set

TYER --- Year

More tags here