This is number one. Old ski sweater, ultra suede bottom. After they kept sliding off I took a little seam in the ankle which helped. But, when we lost one it was sort of a blessing.
Number two. Fleece from an old fuzzy bear Patagonia coat. I honestly thought these would do it. They are a lot like haflinger slippers but they would not stay on either.
Number three. I finally caved and used a pattern I found online for free. They're basically robeez with a rubbery bottom. Finn likes thesebest, too.