What exactly is this part called? I need to find a new one. After some google searching, i'm not sure i found the right piece online.

 

It's called a "FILLER" for the front bumper should come in a set of 2 R&L. It is very unlikely you will find a GM NOS part which would be sold as a single part. Although the A/M part is stiffer than OEM it still will need to be painted with Flex additive in the paint for paint to stick properly. Good Luck