Is a 750 on the Bio E subject test good for top schools like ivies and stanford?
yes. of course it is. it won’t get you in but it won’t keep you out. focus on other things. it shows you are capable enough and now it’s up to other aspects of your application to impress.
88th percentile among the selective subset that would take this test is certainly good for top schools. There will be many higher, but also many lower. As noted above, it won’t swing the decision either way.