Filtering graduate programs with the lowermost entry requirements

[qwerty321]

I am thinking about applying to graduate programs in mathematics in the US/Canada. I had excellent GPA at the undergraduate level in a STEM field and a couple of publications (+close to perfect quant GRE), but my undergraduate major was not in mathematics/mathematical physics (although I did a couple of upper undergraduate math courses) and my publications are not, strictly speaking, in traditional mathematics (perhaps, very applied/computational mathematics, at the most). Also, I am somewhat old to be doing this and my professional record since graduation is somewhat inconsistent. I guess, my chances of admission+TA at very good mathematics departments are close to zero, especially in a post(?)-COVID world.

I would like to know how one would filter out the departments that offer Ph.D. programs/TA with the lowermost requirements. I have seen some subjective university rankings based on peer review, but the peer review is hardly a reflection on how difficult it is to get into a program. Do there exist any statistics about the entry requirements for graduate schools? Otherwise, what would be a sensible methodology for the selection of schools to apply to, given my primary selection criterion?

Edited March 12, 2021 by qwerty321