Lomography.com sell some weird ones.
I've tried Purple but I don't like it very much.
You can also look up "redscale" and try that. You can do it with any colour film but I find it works best with a normal speed negative film. ISO 100 or 200.
Pic related; it's Lomo Purple. They also made a turquoise one, but I was so disappointed in the Purple that I didn't try that.
