SimsService has a Witch costume, a hat and sweater mainly. Also a cat hat, which was more Halloween fun than real Witch. I also found a necklace with a dragon on one of her other creations from the same cartoon series.
hat
There are 11 posts tagged hat (this is page 1 of 2).
A Nature Witch Hat and Medusa Hair
A nature Witch hat, dryad hair and mask and Medusa hair from feralpoodles. You may not thing you would ever use Medusa hair with a Sim, but now that you know its there, the temptation will be there.
A Witch Hat in All the Colours you Should Ever Need
Sparkly Witch Hat
This looks pretty. I haven’t loaded it yet but I like the image preview.
Sparkly Witch Set with a hat, gown and jewwellery from HeavenSent418.
Colourful Witch Hat
Colourful Witch hat with two versions, by Kalewa-a.
Long, Full Skirt Witch Dress and Hats
Dissia has a long, full, Witch dress. Like a ball gown for a Witch.
You can also download the hats. Witch hat patterns. Arcane Illussions – Witch Hat.
A bat dress, and garters, a bikini top and bottom which I haven’t linked to. It’s leaning more towards Halloween than Witch for me.
I do like the Moon Girl Swimsuit with the moon phases around the waist.