This is something I was doing way early this morning. Here, I wanted to show all of you the difference and same between these two ponies, who are both unnamed. The pony on the left is S05E06 Unnamed Earth Mare #2 and the the pony the right is S08E22 Unnamed Earth Mare #2. Now, let’s get to the comparing part.
 
Both of these two share their mane and tail styles, eye, and coat colors, as well as their cutie marks. The difference with the two mares is that the pony on the left wears accessories and the pony on the right does not, and has a different eye type (Pinkie Pie’s eye type).
 
This does not confirm that they are related, however, since background ponies aren’t usually confirmed as siblings and/or families.