There is a page in real OEM with all of those body nuts listed of the different sizes

https://www.realoem.com/bmw/enUS/sho...81#07129904150

I think the second one listed 4222 is the most common one on all the fender liners etc.

Edit - it's not that one, it's 4150 https://www.fcpeuro.com/products/bmw...er-07129904150

The left and right long under plastics had a larger one 26mm I believe to be 07147144276

__________________
'05 E53 3.0 6mt
'17 F30 340ix 6mt
'96 E36 328is, in progress