There may have been a coven just for Wiccans in the past but it ended up deleted for lack of activity or other problems. Currently the board owner is not permitting new covens to form since there are enough here at the moment.
On the other hand, you do have this section of the board on Wicca and it is a good place to ask questions about Wicca and discuss Wiccan beliefs and practices. So it is almost as good as having a specifically Wiccan coven.
Is there something in particular about Wicca you'd like to discuss??