The Lightweight Carbon-Fiber Handguard from Lancer is pretty cool. It’s a free float handguard for 5.56mm AR type rifles and 7.62mm AR type rifles.
The carbon fiber tube is attached to the receiver extension with fasteners so no bonding is required. Additionally, the handguard will remain free floated even if used on a rifle with a fixed sight post due to clearance between the end of the handguard and the fixed front sight post.
It integrates cooling slots that pull double duty as attachment points for Picatinny rail segments. You can customize the setup of your handguard by placing rails only where you need them. Where needed, aircraft grade 7075-T6 aluminum is used.
As you can see, Lancer offers the handguard in extra long, rifle and carbine lengths as well as mid-length (not shown).