I think KLEI makes the only low mass binding posts that I am familiar with but I’ve gone lower mass. To truly go low mass you have to abandon the attachment for lugs. I use BFA style "banana" plugs. they aren’t really banana and make a much better connection.
Cardas is the antithesis of low mass. that is what inspired me to make my own.
Let me know if you’re interested in how I make my own.
Jerry