Golden Showers or Scat
Urinating on a partner, or having your partner urinate on you is, in fact, a popular fetish. The brown stuff (scat) is less so, but fans still exist. These fetishes get into tricky territory. Unlike feet or cross-dressing, there are those who find urine and feces to be profoundly unsexy to an extent that no amount of communication will change. If this sounds like you, it's imperative that you be up front with your partner about this. Hopefully, you can discuss it in a way that's not shaming or judgmental.
If you decide to give bathroom fetishes like this a whirl, remember: safety first. Plastic or vinyl sheets can keep mattresses from being ruined. Better yet, try these activities in the shower (at home or a specialty motel - not a gym, rented hot tub, or the local pool, please).
Zoophilia and Furries
Sexual attraction to animals, or to the idea of having sex with animals, is more tricky territory. This fetish doesn't necessarily mean that a person literally wants to get their giggity on with a dog, horse, or other literal animal. So, it's important to talk with your partner frankly about what this fetish means to them and how they act on it. Furry refers specifically to people who dress up as animals (and may even self-identify as animals), or as a person who wants to engage in sex acts with those who do.
To say you'll need a love of animals to date a zoophile or furry is to oversimplify. You'll need an open mind, a vivid imagination, and probably a costume or two. These can be rented but if you're in it for the long haul, you might want to buy one or have one custom made. Sure, that's an investment, but it's an investment in a healthy sex life!
Voyeurism and Exhibitionism
There are people whose fetish involves either watching others have sex (voyeurism) or having sexy times in places where they are or could be viewed by others (exhibitionism). Obviously, legalities play a part here. You don't want to be peeping in the windows of strangers or having sex in a public park during the day. This fetish can be as mild as not wearing underwear under your skirt or as bold as sexual acts in a public place during business hours.
Like any other fetish play, discussing boundaries is critical. If you decide to partake, venturing outside your comfort zone may be in order. Caveats may include getting caught by strangers, seeing things you can't unsee, and getting arrested. This fetish may even get you on a sex offender registry if the indiscretion is serious enough, so proceed with caution.
You may be unsure of whether or not you want to invite a fetishist into your life. I'd argue that dismissing one as a potential partner without discussion means you could be cheating yourself out of a fun relationship with a fine person. Whatever you decide should be a choice based on information rather than presumption.