There are many, many different chemicals that may contribute to spontaneous combustion.
Yes, there are other chemicals that cause spontaneous combustion in other products and substances. My comment referred specifically to oil-based finishes, the topic of this thread, and it's primarily the metallic driers that are added to oil finishes that can cause spontaneous combustion.
The reason the driers can cause spontaneous combustion is that they cause the oils to oxidize at a fast rate. Without the driers, the oils oxidize at a very slow rate. That's why engine oil doesn't spontaneously combust, for example - it doesn't oxidize fast enough. Add metallic driers to it, though, and it will spontaneously combust.
If you are interested in learning a bit more about this, a couple of references:
A solution to spontaneous combustion in linseed oil formulations, Abrams, Polymer Degradation and Stability, Volume 54, Issues 2-3
Oxidation reactions and spontaneous ignition of linseed oil, Juita et al, Proceedings of the Combustion Institute, Volume 33, Issue 2
These and other references should be available at the engineering library of any tier 1 research university.