I wonder what gem polytreat's weapons be lie and what they are. If one or two don't know how to Summon a Weapon so it would be interesting for one or two of them or even how one of crystal gems to train how to summon their weapon.
After some thinking, I decided on the Triple Threat's gem weapons
Sapphire!Henry: She doesn't use a weapon. She uses her ice powers, future vision, and general speed and strength to get around her problems. I don't think Sapphires have weapons, but she does fine without one.
Nephrite!Charles: She's got a GRAPPLING HOOK! I had a little trouble thinking of a gem weapon that would fit her, but when I started listing out things N!Charles would want to do, I realized a grappling hook was perfect. Summoning weapons doesn't come naturally to her, on account of her being made for flying. It's actually P!Ellie who helps her figure out how to summon it, while they're chasing S!Henry. She isn't consistent at being able to summon it until S!Henry joins the team, though.
Pyrope!Ellie: Axe all the way, baby. You know our girl P!Ellie's a heavy hitter. When pulling her weapon out of her eye, the staff part comes first, then once it's emerged the blades come out of either side. Since as a Pyrope she's a natural fighter, she was already good at summoning her weapon before Era 3.
Labradorite!Chellrey: Combining all three of their abilities, L!Chellrey's weapon is a crossbow! Which is really, really hard to draw, hah. In her earliest conceptions she cannot summon her blade weapon - she can barely do much without falling apart. But as the Triple Threat get closer, learn to trust, and eventually fall in love, Chellrey becomes more stable and more powerful, with a more unified look to match.