And need to know the features to look out?
Why don't you say so
Most glider pilots prefer brown orangeish tinted glasses because they improve cloud contrast by attenuating the blue spectrum. It is believed that you can observe thermal activity better with them especially at the edges of cumulus where you definitely see haze threads you would not see with greenish tints. The grandfather of those are Zeiss Skylet glasses. But those Serengeti Drivers or others are probably not so bad as well.
Often glider pilots prefer not so dark tints, because you sometimes have some twilight underneath bigger clouds. Those Skylets are for example available in 70% reduction of transmission whereas 85% are default in most other applications.
As there are no possibilities to shade from above or the sides big, curved and tight wearing frames are preferred.
Big no are thick temples, because they restrict your field of view when circling in thermal with other gliders. You can detect motion in this area surprisingly well.
Big no is polarization due to LCD compatibility. You might want to get a fancy moving map ... No problems to be expected with the hood though.
Personally I found some ruggedness useful on airfields as well - well not only on airfields so that might be a peronal thing
. Hence my preference of mineral glass - but that's not compatible with high base curve and exotic tints unfortunately.
I am afraid gliding sunglasses are rather special and you won't score with them on the beach
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Cessna drivers have other specific needs (eg they are well shielded from above but have uncomfy headsets to wear) so probably have airline pilots. So there are no generic aviation sunglasses although some are called aviator.