Oboe

From Oddwinds

The Oboe family is mundane, because the oboe itself is, but the family has odd members.

Besides the mundane oboe we have:

Oboe d'Amore

English Horn (Cor Anglais)

Tenor Oboe

Baritone Oboe

Of these only the English horn is mundane. (Authorities differ on whether the English horn should be considered a member of the oboe family or a distinct family-of-one.)