Another one I'm trying out is Grist. They have Python scripting for functions and their way of viewing multiple tables on one screen is helpful. So far I'm liking it, although it misses some things like prefiltered referential selection boxes, and I would like more entry validation for deployment to typical internal end users. They're also not great at marketing themselves.

I looked at Budibase but it doesn't offer self-referencing table relationships and the CSV import process doesn't seem to support updates as cleanly as Grist. And the interface seemed kind of sluggish to me.