var d = new DirectoryInfo("PATH-TO-YOUR-FILES");
var files = d.GetFiles().Where(f => f.Name.StartsWith("11"));
You can add more filter if you want. By adding
.OrderByDescending(f=>f.CreationTime)
I will get newest files on top. And if I don't want all files I can simple add
.Take(10)
to get the 10 newest files and so on...