Suit designed for karting – as others have said it must be abrasion resistant. Same for gloves. A rib vest is a good idea. You might be able to get away without it in LO206 if the track and curbs are smooth, but rib injuries are common, painful, and take a long time to heal.
Neck braces may be mandatory – check your rules! I’ve never been a fan of the foam donut neck collars. I think they’re probably worthless in a rollover except to stop your helmet cracking your collarbones. I’ve used the EVS brace for years, but there are others out there at various price points.