You have to name a specific organization, and that organization must be registered with the IRS as an exempt organization eligible to receive tax-deductible donations. Turbotax does not have a list of all eligible organization, you need to verify that yourself with the organization or the IRS lookup tool.
https://www.irs.gov/charities-non-profits/tax-exempt-organization-search
Then, if you are using "Guide me" (or ItsDeductible), this function does not have every possible item, and the values may not be correct for your area or the things you donated. The IRS can (and has) audited turbotax customers and assessed extra tax because the customer could not prove that the generic item values were appropriate for their specific items.
You can enter a custom donation of items with a generic description like "supplies for animal rescue" and the dollar total. You do not have to list every single item on your tax return. However, you should keep your specific records of what items you donated and how you determined the values in case of audit.
