LED capable of either IR or visible light (not at the same time)
Emitters with both infrared and visible light can be found by searching for "infrared dual emitter" or "infrared dual LED". 

For instance, one such part available in my geography is the Osi Opto DLED-660/940-CSL-3, a side-emitting LED with 660 nm red and 940 nm IR, independently controllable (common anode).



The bidirectional (CSL-2) type might be preferable for simplistic applications such as mentioned by OP, where inverting the voltage would switch between IR and visible emission, without both being needed simultaneously.