On the one "loose" fit one, you may want to try CRAFTSMAN Sears/K-Mart/DoIT Center ones in both 11mm/12 point & 7/16"/12 point if buying new. Remember, tools do wear, and some sockets fit snug because they are more accurately broached and some have plating which may affect the final fit. If you have older sockets, they do wear if used often...hence the Lifetime Guarantee/exchange should allow a swap, as the Thin Wall construction can cause the socket to crack if highly stressed, been there...!
My toolbox is an amalgam of Craftsman, Proto, Snap-ON, MAC, Thorsen, Allen, Crescent and others collected over the years. And when you get into the smaller metric sizes, there are "half-sizes" that are common, like 4.5mm, 5.5mm, 6.5mm if you look hard enough, as well as 16mm, 18mm, also rare...