The BladeForums.com 2024 Traditional Knife is available! Price is $250 ea (shipped within CONUS).
Order here: https://www.bladeforums.com/help/2024-traditional/
I made a knife with terotuf once. I didn't weigh it or anything, but it felt lighter than g10 and micarta.
Stabilized balsa? Kidding
Hoss
I go with cork. I have a couple fishing fillet knives with cork handles, they float.
Of course they are not heavyduty knives either.
Honestly, some nice indian rosewood would be surprisingly light. Its only about the density of hard maple "One of the lightest of the rosewoods" but still rather strong. Ive got some if you like