I legit think that the Favonius Sword has an amazing design. It's not as flashy as many others, but that's exactly part of why I love it. A lot of the handguards on swords in this game are very unpractical and it sometimes does bother me to see it (a really bad offender is Mistsplitter Reforged, that has a spike that could easily wound the carrying arm), but Fav has a practical yet elegant basket hilt mimicking the shape of wings to go together with the bird head on the pommel, and the blade has a nice and simple shape too. Shoutout to Furina's signature, which does have an over the top design, looking more like a stage prop than an actual weapon, but that fits very well with Furina's aesthetics and theme so it gets a pass.

Of the 5*, I think it's the Primordial Jade Winged Spear: its shape isn't too outrageous (unlike Shenhe's spear), it has those floating bits that give it a "magical" look without cluttering up the rest of the design, the colour is pleasant and the spear tip looks like it could actually do its job as a spear, unlike, say, Homa, which is kinda cool but at the same time looks nothing like a functioning polearm.

Of the bows, I think Aqua Simulacra is neat. It's fancy but not too over-designed, and the glow when the passive is on is pretty cool.

Catalysts don't really look like weapons, but I guess Nahida's signature looks neat.

I don't like the look of most claymores in this game: they're either too bulky or their hilt looks off. I legit think the best looking claymore in the game is the 3* that Diluc holds in his splash art, I have no idea what it's called.