"'The Men of the Sea,' it was said, 'send before them a great cloud, as a rain turned to serpents, or a black hail tipped with steel;' and in those days the great cohorts of the King's Archers used bows made of hollow steel, with black-feathered arrows a full ell long from point to notch."
Mae govannen, mellyn, and well met! This suggestion concerns one of the most feared weapons in all of Middle-earth: the Steelbows of the Archers of Westernesse.
These bows would be found very, very rarely in hidden chests of Gondorian houses in the Pelennor and Dol Amroth, as well as Numenorean Ruins, Dunedain houses, and Arnor Ruins. I wouldn't rule them out spawning in any Black Numenorean houses in Mordor either. They would naturally be uncraftable, but would be terrifying on the field of battle. Their range would be 190%, and their damage 12-18, but their draw time would be 35-40 ticks, since this bow is massive and deadly. Their durability would be very high, but they would not be repairable, and only spawn with about 2/3rds durability. However, they would be combinable with other Steelbows, and could recieve modifiers.
These bows would also, due to their size, only work with a unique arrow type. Called the Numenorean Arrow, they would be found everywhere the Steelbows are found, but somewhat more commonly. They would also be given in miniquests, in place of coins at about a ratio of 1:2 arrows to coins. The Gondorian in question would give some quote about how they found a quiver/bundle/handful of strange arrows in a cellar/attic of a relative, and thought they would make a fine reward. (credit to Recneps)