What’s the best avenue to find abandoned pets a home?

I’ve recently found a dumped Russian Blue (aka Archangel Blue) kitten at an elementary school. It was super dehydrated and could barely walk. Gave her a bunch of fluids and food, took her to the vet and the vet said she’s fine. Anyways, I’ve been calling/emailing multiple shelters and foster agencies all weekend and no one will respond or take her. Anyone have any suggestions?