Krypton is used in halogen sealed headlights. The element produces high, brighter lights by allowing thinner filaments to be used with acceptable useful lifetimes.
Krypton and Argon gases create fluorescent lights, photographic projection lamps, and electric lamp bulbs due to their bright color. Krypton-86 is most used and combined they create a greenish glow. KrF is also popular in fluorescent lights.
Krypton is also used in airplane runways because it responds fast to electric current.
KrF2 is a powerful oxidative fluorinating agent and is a only used in labs.
Krypton and Zeon are used in multi-pane windows because they reduce the heat that is transferred from outside to inside.