free-for.dev is a wonderful list consolidating a ton of “as a service” offerings that folk interested in developing websites or other software and infrastructure might be interested in which have a decent cost-free tier. Ideal for the inveterate hobbyist tinkerer who wants to play with shiny new nerd toys but isn’t in a position to invest a lot of money into the act.
Usually, but not always, the free tier is offered as a potential gateway to a paid tier. That’s often worth considering doing, if nothing else then to support the services you like. But the list is constrained such that the free offering must be both long term and useful.
These are all as-a-service offerings rather than self-hosted things. You can easily help out by contributing to the list.
My personal use-case for it this time was finding a way to implement a contact form on a static website. It saved me a lot of time and effort vs Googling and hoping for the best.