First of all, fuck you Scooby I'm so jealous. Now that that's out of the way...

One thing I recommend having in a basement is something to help counter the lack of light you'll get. Obviously you want the lighting to match the mood, but the more options the better. I recommend led strip lighting because it takes up no space and also you can change the colors via remote.

Another really cool idea I love is mirrors. Mirrors on the wall (or in place of a wall) are sexy and help brighten the place a bit. The only time I would not recommend mirrors is if you plan on filming a lot. You can buy tiles of mirrors the stick right onto the wall.

Doing any fireplay, waxplay, or lighting candles? Keep a fire extinguisher down there. Also a trauma kit, can never be too safe.

If you have enough space and enjoy a drink, consider adding a bar to the side as well.

Also, get one of these

https://www.amazon.com/AcuRite-Humidity-Thermometer-Hygrometer-Indicator/dp/B0013BKDO8

It's a basement, you want to make sure it doesn't get too humid down there or your furniture will degrade.

If you post more details about what you're thinking I will try to bounce some more ideas off that as well