I have no knowledge regarding the Mahayana Sutras, but to whom did the Buddha teach these ? Shouldn’t his closest disciples be aware of them ?
Your question seems to imply that the Buddha actually taught Mahayana sutras. I would recommend reading previous discussions on this forum.
On Wikipedia you can find some origin theories about Mahayana: Mahayana - Wikipedia
And for a more academic perspective: (PDF) Early Indian Mahayana Buddhism I: Recent scholarship | David Drewes - Academia.edu
Thanks a lot.
Beside the historical complications of tracing Mahayana texts to the Buddha, it should be noted these are quite explicitly stating who the Buddha was teaching to.
And it usually is a mix of monks, kings and lay people.
As SuttaCentral does not host such texts (they’re not early remember) you may have to look for them in and through other sources like Wikipedia.