Any situation where you cover tech in place and no tech, but not the techrolls is a 50/50.
Any time there are 2 basic DI options out of a throw and you cover one based on a read, it's a 50/50.
There aren't many in neutral except for in micro-situations where you've made a number of your opponent's options obsolete by your positioning, and these are very specific scenarios although they happen often.
There are cases in edgeguarding too against fast recoveries, like if you know fox/falco's dj will put them even with the ledge, you can cover the side-b, but they might up-b. Not a great example because in many cases you can cover it all.
There are a ton. And some arent quite 50/50, and could be better or worse than 50% based on the situation, with positioning, platform location, DI options, percent, etc.
You're asking a lot.