since we don't usually have side markers/indicators on the fender/wing, the law requires an orange reflector somewhere on the front corner of the car, facing the side. also requires a red reflector on the side near the rear of the car, and 2 more red reflectors facing rear. most times these are integrated into existing light housings to have a cleaner design, but not always.
law here also states you must park in the same direction traffic is flowing. most (but somehow, not all) states also require a front license plate, and that's reflective, so it's better than nothing.
i learned about separate left and right parking lights after seeing separate fuses and relays on (i think) an older Jag, and asking about it.
IMHO, with today's bright headlights and bright retro-reflectors (their proper name), i don't see the need for actual illumination on a parked vehicle. just need to get drivers to focus on DRIVING instead of their phones or whatever.