https://www.mcmaster.com/screws/hex-head-screws/
or Digikey:
https://www.digikey.com/en/products/filter/ceramic-capacitor...
or PCpartPicker:
https://pcpartpicker.com/products/motherboard/
compared to trying to find the same products on Amazon or AliExpress. Many of the products are available, but every product on those examples can be filtered against comparable products by the specs that matter to the engineers doing the selection. On other sites, the metadata is generated inconsistently by individual sellers.