Weapons in Grounded 2 are can be either found or crafted but most weapons are indeed craftable only. There are a ton of recipes you can use and even more crafting materials involved in these weapon crafting recipes.

Speaking of crafting materials, one of the most common materials in Red Ant Parts. I have a separate guide on how to get Red Ant Parts for crafting so do read it if you need this crafting materials.

Grounded Weapon Crafting Recipes

There are close to 40 craftable weapons in Grounded 2.

ItemTierRecipe
Pebblet SpearISprig (2)
Crude Rope (1)
Pebblet (1)
Stinger SpearIIBee Stinger (1)
Bee Fuzz (5)
Silk Rope (3)
Mosquito NeedleIIMosquito Beak (2)
Silk Rope (2)
Mosquito Blood Sack (2)
Crimson SaberIRed Ant Mandibles (2)
Red Ant Part (3)
Grub Hide (2)
LarvalanceILarva Spike (2)
Red Ant Part (4)
Crude Rope (2)
Roach ClubIIRoach Head (2)
Roach Chunk (3)
Blueberry Leather (2)
Weevil ShieldIRaw Weevil Meat (2)
Grub Hide (2)
Crude Rope (1)
Crimson BuckletIRed Ant Part (4)
Mite Fang (4)
Grub Hide (2)
BombucklerIIBombardier Part (4)
Silk Rope (2)
Spine Nub (3)
LadyguardIILadybug Part (4)
Crude Rope (2)
Sap (3)
Red Ant ClubIIRed Ant Mandibles (3)
Red Ant Part (4)
Sap (3)
Crude Rope (2)
Spicy CoaltanaIIISpicy Glob (2)
EverChar Coal Chunk (5)
Wolf Spider Chunk (4)
WarhammerletISprig (3)
Sap (3)
Pebblet (3)
Mantis BladeIIIPraying Mantis Claw (2)
Praying Mantis Chunk (4)
Lingonberry Leather (3)
Mitey ClawsIMite Fang (4)
Mite Fuzz (3)
Red Ant Part (4)
Northern ShreddersIINorthern Scorpion Chunk (4)
Scorpion Venom (2)
Spine Nub (3)
Silk Rope (2)
Ice SicklesIIIMint Glob (2)
Northern Scorpion Pincer (2)
Northern Scorpion Chunk (6)
Weaver DaggersIIOrb Weaver Fang (2)
Orb Weaver Chunk (4)
Silk Rope (2)
Wolfsbane FangsIIIWolf Spider Fang (2)
Wolf Spider Chunk (4)
Spider Venom (4)
Silk Rope (2)
Sprig BowISprig (3)
Gnat Fuzz (4)
Crude Rope (2)
Spider StringerIIOrb Weaver Fang (2)
Orb Weaver Chunk (3)
Silk Rope (3)
Wolf StringerIIIWolf Spider Fang (2)
Wolf Spider Chunk (3)
Silk Rope (3)
Spider Venom (2)
Arrow (10)IMite Fuzz (2)
Thistle Needle (5)
Feather Arrow (5)IICrow Feather Piece (1)
Silk Rope (3)
Venom Arrow (5)IIFeather Arrow (5)
Spider Venom (1)
Gas Arrow (5)IArrow (5)
Stinkbug Gas Sack (1)
Mint Arrow (10)IIFeather Arrow (10)
Mint Shard (1)
Spicy Arrow (10)IIFeather Arrow (10)
Spicy Shard (1)
Disruptor Arrow (5)IIFeather Arrow (5)
O.R.C. Receiver (1)
Pollen Arrow (5)IPollen (2)
Arrow (5)
Scorching OrbIISpicy Shard (4)
Bombardier Part (3)
Boiling Gland (1)
Glacial StingIIIMint Shard (4)
Northern Scorpion Stinger (1)
Pine Needle (2)
Rocky Rounds (25)IPebblet (25)
Acid Gland (3)
Groundy Rounds (15)IWeb Fiber (5)
Pollen (2)
Pointy Rounds (25)IIThistle Needle (20)
Crow Feather Piece (1)
Sappy Rounds (15)IISap (5)
Salt Shard (2)
Burny Rounds (10)IIEverChar Coal Chunk (2)
Boiling Gland (1)

To craft these recipes you can use the Workbench aka the Workstation. Upgrades work through the Workstation as well.