OK when did you last use the car, what were you wearing - chekc that
what did you do when you came in - e.g. shopping unloading - check the area involved, or did you go to the loo and put on the side etc, what bags did you have with you - check those, check all usual culprit areas
Then start on the random areas like the toy area, pans for the toy kitchen, inside shape sorter balls, ball pit, little houses, toy cars, check round the TV - thank your lucky stars we have moved beyond video (The slot was always a good bet with my youngest brother!!)
If it was a few days ago check areas where you have been or little ones have been playing etc. Oh and don't forget to check the outside door& Car