Mist/Fog particle textures

Does anyone know anywhere inworld where i can buy some decent textures for use with the particle system?

I've done the usual 'Find' but drawn a blank and could spend the rest of my life searching through all the texture shops so I thought I'd ask. I'm trying so make a sort of 'dry ice' effect for fun. I know I could buy it off the shelf but I'm having fun playing with particles at the moment.

Thanks in advance!