I have searched through Rebrickable and Bricklink and can't seem to find this part. Does anyone know what it is or what set it is from?
1Have you looked at the bottom? Try to find a very small number there.– MołotJul 30, 2021 at 14:36
50948 Wedge 4 x 3 Cut Back with Cutout, 2 Studs
ATR 4 (8657) set is the only to include this element in Light Bluish Gray
1In that color, it might only be in one set: <bricklink.com/v2/catalog/catalogitem.page?S=8657-1>– RSchulzJul 30, 2021 at 15:00
1Hope you don't mind me adding set you've mentioned into your answer.– AlexJul 30, 2021 at 18:54
1Can you teach us how you find this? Is there a lookup function or a description bot somewhere, or did you know the piece, or did you just examine them all one by one?– KonerakJul 30, 2021 at 21:26
I tried a variety of google image searches; Based on my browser history from earlier, the one that finally worked was "bricklink curved cutout". I recognize this piece (I don't have it in this color) but I couldn't spot on any builds I can easily lay my hands on, and I think I stored it in a place that is a bit hard to get to at the moment, so I just googled a few things until it worked.– RSchulzJul 31, 2021 at 3:44