What worked for me during med school apps was going on walks by myself and asking myself every possible question they could throw out. I'm sure residency questions won't be as "on-the-spot" as med school ones, but I had an answer for all the things they asked me and felt super equipped just by doing the above.
You can google what common interview questions are, but for the medicine-specific ones just look around reddit or think to yourself about the stuff that is going on. I think it's a completely fair question to ask us what we feel about XYZ going on in healthcare (midlevels? We should all have a solid, evidence-based opinion. Covid and vaccination? The same).
Also have some canned questions that are unique that you can pull out of your pocket when prompted. I don't wanna' share mine publicly, but basically you're assessing the stuff that you can't learn on a website!