I've used dryer lint (particularly that derived from drying *cotton*, don't know how polyester lint would behave) and cotton balls with vaseline, or sprinkled with wax shavings.
I would be real interested in seeing a REGIONAL guide to naturally-occurring tinder - I know they suggest fatwood in areas where pine trees abound, but what about other areas? I know my Dad mentioned being on a trip with natives in Peru, and one of the Indians came back with some type of palm leaf for starting the fire (he said "this is our kerosene" ) - it burned very well even though green, but I never learned to identify that type of palm in the jungle. What would you use in say, desert-type ares, such as west Texas? Will cactus needles burn?
I have some magnesium bars, but have not found it very easy to get the shavings from the bar. I hate the idea of ruining my knife edge on it, and even when i tried it seemed to take a long time to get any shavings (and was difficult to concentrate the shavings where I needed them).
I'll admit I haven't tried the RAT firestarter yet, since I already had a couple others, but after seeing recent reports here that it performs better, I may just have to give it a try.