Maybe: https://en.m.wikipedia.org/wiki/Carbon_disulfide https://en.m.wikipedia.org/wiki/Carbon_disulfide Doesn't appear that many substances have auto ignition

Maybe: https://en.m.wikipedia.org/wiki/Carbon_disulfide https://en.m.wikipedia.org/wiki/Carbon_disulfide Doesn't appear that many substances have auto ignition as low as 100c. If you're hunting for easy to ignite stuff, it might be better to go for low flash point stuff, and strike a spark? Eg gasoline will work in pretty cold environments with a flashpoint of - 43c.