I'm always on the lookout for services that offer free tiers for some experimentation - particularly around databases, "DaaS".

Developers and Open Source authors now have a massive amount of services offering free tiers, but it can be hard to find them all in order to make informed decisions. This is a list of software (SaaS, PaaS, IaaS, etc.) and other offerings that have free tiers for developers.

Source: free-for.dev