SDS Software
I am updating our SDS and I was just going to make an excel spreadsheet and link the PDF's of the SDS to it. However I thought I would reach out and see if there is anything cheap or free that other people are using or could share that works easily and is easy to keep updated.
Succeed Risk Management System is a good safety/training database that also includes MSDS indexing.
Site-hawk is a good option. https://www.sitehawk.com/
Not sure on the pricing but it is an easy manageable solution that can be audited.