glare8217 There's no service or app that I have heard of that analyzes other apps to detect the presence of a Google-certified OS requirement, or other "integrity" checks. It would be a daunting task to curate a list of apps that do work fine on GrapheneOS, because most of them are working just as fine as on stock PixelOS.
Some banking apps are problematic; there's a community curated compatibility list here.
Some apps check for a Google-certified OS, which GrapheneOS cannot spoof (or a spoof would likely break again in the near future). Most apps don't do that. I think your best bet there is to search the forums, or else start a new thread asking about a specific app. I find this Duckduckgo search to give me slightly more relevant results than the forum software's search function. If you cannot get an answer here, you can always search or ask in the community chat rooms as well.
A community curated overview of all non-banking apps that check for Google certification could be possible, of course, but would also require maintenance effort. It's also not a fun exercise, I imagine, even if the list is not very long.
Some Pixel exclusive features and apps don't work on GrapheneOS because they require privileged access, including some Google apps. A community member made a compatibility overview of many of these here.