I am trying to find a mold to make a border similar to this cake. Does anyone know where I may find something like this? Really appreciate any help.

I have never seen this particular mold, but here is a nice one.  I ordered the same one from this company and it was perfect.  It does take two or three weeks to arrive.

https://www.wish.com/search/Pearl%20border%20silicone#cid=58c3ab262a53b67019700212

Doesn't look like a border mold to me.  Looks like they made jewels in white and arranged them by hand, adding the little pearls in a pattern.  I only see two different jewels used, so pretty much any jewel mold should work :)