Other than Artifacts, the character's weapon is the build's finishing touch if they can do their role correctly. Some weapons often allow some characters to deal massive damage to foes or be an efficient support for their team. Here are some underrated weapons that have potential but aren't popular yet.
This bow was previously introduced as one of the new 4-star weapons included in the limited weapon banner during the Klee rerun banner in Patch 1.6. This bow synergizes well with Bow character carries as it boosts Normal Attack and Elemental Skill damage when the character fights. The weapon's synergy with active playstyle and low cooldowns make it a strong weapon.
When leveled up, it works well on Fischl who benefits from the weapon due to its stats and playstyle. It also works on other Bow characters if built for Physical Damage.
The Alley Hunter
This bow is unpopular as its effect works similarly to the Thrilling Tales of Dragon Slayers catalyst. Characters who use this bow must hang back behind another party member to fully use its effect. In co-op parties, this weapon's effect is rendered useless as a full stack of player teammates prevents its wearer from switching characters.
However, this bow has a massive damage boost for its wearers upon taking the active spot in the party. The damage boost can hit at the maximum of extra 20% damage.
If Amos Bow is not available, this can be a viable subtitute for Ganyu as it boosts her attack and the weapon buff will be good for one fully charged arrow.
This weapon has been unpopular before as it gave Elemental Mastery during the time when Critical stat builds were popular. However, the latest update buffed Elemental Mastery which allows some characters to deal high elemental reaction damage.
Currently, it makes sense to use it on Xiao due to his Anemo element and Swirls but this character benefits well on Critical builds. Potentially, Xiangling has a better synergy with this weapon as her Elemental Burst persists even when switching characters.
Moreover, Xiangling has been a popular character as her Elemental Burst allows players to breeze through later floors of Spiral Abyss without much difficulty. All she needs is the right team and artifact build to easily clear out enemies for you.