Drawer Slide Attachment Clip - Need Help

We moved into our (new to us) house this last summer and have been fixing little things here and there but there is one thing I have not been able to fix. In my daughters bathroom the vanity has several drawers. One of them would not open or close correctly. When I looked under the drawer at the slides I noticed one of the slides was not attached and was missing this gray clip (shown in picture). I have searched everywhere and cannot figure out what these are called or where to find one. Any ideas?

 

I assume you've looked for any manufacturer ID or numbers anywhere on the rails/slides?

I had a similar situation a few months ago.
The rear most plastic slide bracket/hanger support on a kitchen drawer had cracked after 24 years, leaving the drawer inoperable.
Zero info to be seen on the slides.
After hunting through countless Google search images I finally found the matching bracket. Obsolete. No longer available.
I was about to order a completely new pair of slides to retrofit when I found an ebay seller that was 3D printing replacement brackets. Worked great.

It might be easier to just find a replacement slide pair.

 

Two places I would look for replacement parts are Lowe's stores or ACE Hardware. Both places have quite a selection of drawer replacement parts or possibly a part close enough that it may work just as well. There are drawers full at both stores. Ask where they are and it may take awhile to search through them all, but very likely you will find the pieces you need
Tnake the old piece with you for comparison. May save another trip because it looked simian but wasn't!