There are lots of different types or categories of chords. You must not learn all of them, but by learning different types of chords your guitar playing will expand.
The types of chords covered:
Minor add chords are included in the Add9 chord guide. This section was earlier found on this page.
Chord types and music styles relationship
Yes and no. Certain chord groups can be typical or overrepresented in certain styles, but it's far from a rule.
Anyway, are you interested to learn a specific style, here are some guidelines. As mentioned, this is no strict relationship between groups of chord and music styles, but as a generalization the information below could be good to know.
Blues: dominant sevenths (7th chords)
Jazz: many different types including 11th and 13th chords.
Funk: ninth chords (9th chord)
Punk: power chords (5th chords)
Bossa nova: 6/9 chords
Besides, for rock guitar playing one thing to look into is barre chords and in the singer-songwriter area open chords are fundamental (in both these cases, it's more as concepts or techniques than groups of chords).