The one with the woman who inherits the cottage and gets entangled with a coven or a local witch or something like that had some nice writing but I thought the plot was dumb (don't remember exactly why, but I usually dislike stories about covens)

Could that be Thornyhold? I haven't read it in years, but it's the only one that sounds even remotely like. Touch Not the Cat has a sort of clairvoyance, but no coven.

I love The Crystal Cave. Along with Phyllis Ann Karr's The Idylls of the Queen and Elizabeth E. Wein's The Winter Prince, it's one of my top favorite Arthurian retellings.