Linked from
The 11 pages that link to Pyrophoricity, each with the reason it gives.
DiboraneRelated: Diborane can ignite in air, making oxygen exclusion essential during handling.
MischmetalRelated: Fine particles abraded from mischmetal-rich flints heat rapidly and burn in air.
DiphosphaneRelated: Diphosphane can ignite in air, a hazard central to its handling.
n-ButyllithiumRelated: Concentrated n-butyllithium solutions can ignite on exposure to air.