I have been interviewing different website programs as well! ShelterLuv has a foster sort feature and can show when they last fostered but it would also duplicate your animal info in PetPoint. I don’t know if you could use it only as a foster roster as their payment method is based on adoption processing…
another website I’ve been using is JotForm surveys and spreadsheets. Your data can be collected and transferred over to Google Sheets as well! You can have 5 free forms and 100 submissions! Create or search for templates.