If I were interested in assembling an authoritative, up-to-date list of trusted CAs, would be reasonable to source lists from the major trust store providers and select only those CAs trusted by all of them? I know it's possible to be a lot more sophisticated and that even that can be flawed, but I'm hunting for a simple-to-follow criteria for now.
The CCADB tracks the various root programs, so you could do this today[1]. In practice however I think you’d be best off just using the Mozilla root program; I believe they’re as (if not more) strict than the corporate root programs in terms of inclusion.
