I use Okay Naturals coconut leave in conditioner most days. It does not need washing out, you just run it through the hair and use like a styling product. It adds a lot of moisture so prevents dryness, plus helps get rid of any 'puffiness' in a hair system and can provide a bit of hold without stiffness too. I love it.
I've tried various leave in conditioner sprays too by the likes of Hask and some other ones from hair system supply websites. Stuff with UV protect to help prevent fading is good too.