LGB hook and loop pretty much fills that bill as could K’d which are a clasp like coupler much like real USA railways use but can take more effort to fit.
I suppose the question is why you want a standardised coupling and what has caused your wish to find one. Your Shay is using "link and pin". What else are you using on your locos and rolling stock ? There is also the issue of differing coupler mount heights. It may not be as straightforward as you might hope. There is also the matter of aesthetics, what pleases the eye most.
Kadee is a great product, a lot of hobbyist standardise on them. They are all of the "knuckle" type. Their chief benefit are the multiplicity of height and mounting options they offer on a standard coupler type. I use them a lot to get around coupler height mismatches caused by some manufacturers' historic design preferences. It shows me to match to of the NMRA Fn3 height standard across all the US style locos and stock I operate. I also use them on kit built US stock that are not supplied with couplers. Take a look here
Large Scale Coupler Conversions and
G Scale Couplers - Couplers - Shop by Category I also have 16mm scale locos and stock but I use a different standard and couplers for those, mostly "chopper" types. Max
My Aristocraft 20ft Gondola (1:29 scale) fitted with a "link and pin" (Ozark Fn3/1:20.3 scale height) and lying beside it a Kadee "large offset" truck mount coupler, that when mounted on this wagon will also operate at the NMRA Fn3 scale coupler height. That wagon is used to couple mismatched stock (refered to as a match wagon), you an mix different couplers and heights at either end and in any combination. As well as those shown it has available, as supplied, Aristocraft/USAT/Big Hauler/LGB height "knuckle" coupler, likewise "hook and loop" type and 16mm scale height centre dumb buffer and chopper coupling styles. Another option to concider ?
