I sense the OP was being ironic and doesn’t actually expect any sub-350g rim to put up with bad landings on 6ft drops!
The stans 455 is a 455gram rim and thats one of the lighter one. I think the crest basically is the lightest rim at 440grams or something.
The 455 doesn’t exist… Stan’s did the ZTR 355, which was 355 grams and was replaced by the slightly lighter Crest, there’s the Alpine (replacing the Olympic) at c320g, and as said the Podium MMX, IIRC mine are 283g and 285g, seem plenty strong enough. Done 3 foot + drops on them, not 6 admittedly! They are a race wheel though.
AM don’t sell individual rims so suggestions for a suitable replacement appreciated.
Have you actually asked them? Just because they don’t sell after market doesn’t mean they won’t repair, in their interest to have one of their rims after all!
If not I’d get a white Crest or Alpine though.
On the uber lightweight Innolite do <250g clincher rims. Meant to be rather fragile!