Role Play is another one of those things that can traverse the spectrum of slightly kinky all the way to beyond extremely kinky.
In the slightly kinky realm we have professor/college student, or doctor/patient, or even john/prostitute. Those things can also be extremely kinky, if you choose, but apparently even mostly vanilla couples can have fun roleplaying those scenarios.
A little more kinky is the abduction or burglar scenario, where you are simulating rape. Those can actually be the most violent, where one person is fighting and the other trying to subdue them, so be careful with those.
More complex roleplay can involve a real slave fantasy situation. If you've both read a fantasy book you enjoy (like, say, Owned And Owner) then you could create a scenario plausible on that world, or in that universe. If you want to stick to planet Earth, you could imagine some sort of human trafficking situation, where you've been kidnapped and are being trained as a sex slave before being sold. Those scenarios can begin with a cuffed or otherwise restrained prisoner/slave, so they tend to not be as violent as the kidnapping or burglar type scenarios.
There is also the mad scientist scenario, a little different (and scarier) take on the doctor/patient.
We have a role playing scenario that my husband particularly enjoys. It's a bit complicated to explain, but it's pretty simple to play out. Imagine a world where people can buy sex slaves, and not all of them have the constitution to punish their slave as he or she needs to be punished, or rather, they don't follow through with their training, and before long they have what appears to be a poorly trained slave. There will be "Master Punishers" that these men pay to re-train their slaves when needed. Slaves know if they start failing in their duties they will be sent to a Master Punisher for a few days, or longer. This keeps most of them on their toes, but some still need to go for retraining occasionally. In our scenario, I come in through the garage door as a restrained slave, cuffed and blindfolded, and we spend whatever time we have without the kiddos with me being "re-trained". And not just retrained, but retrained by a cold professional who is only interested in results, not feelings. We don't have the opportunity to do it very often anymore, once upon a time (before kids) we'd begin this on Friday evening and end it on Sunday evening. Now we're lucky if we have 24 hours of it once or twice a year. When you can do it over a period of days then it can involve sleeping in restraints, loss of bathroom privileges without permission, loss of food choices, near-constant plugging and bondage, and a whole lot of punishment type impact play that just goes on and on and on. Some of those things are normally a hard limit of mine, but I'm willing to endure them for a very short period of time (a day or two) in order to have fun with a role playing scenario. I've actually written part of a manuscript based on such a world, but it was a bit too close to home and I stopped it partway through. Perhaps someday I'll go back to it.
Other scenarios involve animal play, where one partner is a pony, a puppy or dog, or a cat or kitten. Some people enjoy the blackmail scenario, where you pretend one person has knowledge that could get the other in trouble and bargains for sex in order to not tell the secret.
The important thing to remember with any role play is that you negotiate ahead of time so it is clear what can and cannot happen, and that there is a safeword in place in case things get too intense.
What is your favorite role playing scenario? Are there any toys or accessories you need in order to make them more realistic?