Bat'leth

A bat'leth, or sword or honor, was a traditional Klingon bladed weapon who resembled a crescent-shaped, double-bladed scimitar. A bat'leth was typically approximately 116 centimeters long, with blades of composite baakonite, weighed about 5.3 kilograms, and had an exterior hand grip diameter of 5 centimeters. 

Bat'leths in fanon
Jeffrey Higdon was given a bat'leth by the Cha'ouw Emperor. ("Star Trek: Black Hawk")

Jack Long was a skilled bat'leth fighter and a non-Klingon that managed to get into 3rd place in a bat'leth tournament. ("Starship Independence")

Jack Marone was a runner-up in the Forcas III bat'leth tournament. ("Star Trek: Generation Fleet")

Relm won a bat'leth from Golar in a bloodwine-drinking contest. She also used a bat'leth to fight zombies when Klingon zombies boarded the RIS in late 2384, in search for Romulan brains. (: "Marianela", "Eidolon")

Florence Finney was apparently sufficiently trained in bat'leth combat to be able to split a bloodwine bottle open with a bat'leth.