String

Dropped by

• Cat
• Cave Spider
• Spider
• Strider
• Aerbunny (The Aether)
• Carminite Broodling (The Twilight Forest)
• Daemonium Pestis (Neo Vitae)
• Hedge Spider (The Twilight Forest)
• Ice Spider (Iron's Spells 'n Spellbooks)
• King Spider (The Twilight Forest)
• Man O' War (Oh The Biomes We)
• Nightfall Spider (Eternal Starlight)

And 7 more.

Dropped when you break

• Cobweb
• Tripwire
• Ancient Vase
• Black String Curtain
• Blue String Curtain
• Bound Block of Cardboard
• Brown String Curtain
• Cyan String Curtain
• Flax Plant
• Gray String Curtain
• Green String Curtain
• Light Blue String Curtain

And 10 more.

Found in chests

• Bastion Bridge
• Bastion Hoglin Stable
• Bastion Other
• Desert Pyramid
• Pillager Outpost
• Simple Dungeon
• Woodland Mansion
• Ancient Temple Basement (Deeper and Darker)
• Ancient Temple Fountain (Deeper and Darker)
• Bandit Towers Barrels (When Dungeons Arise)
• Bandit Towers Normal (When Dungeons Arise)
• Bandit Towers Rooms (When Dungeons Arise)

And 144 more.

Caught fishing

• Junk
• Open water
• Junk (Eternal Starlight)
• Junk (The Bumblezone)
• Open water (Eternal Starlight)
• Open water (The Bumblezone)

Brushed out of suspicious sand or gravel

• Trail Ruins Common
• Ancient Shrine Suspicious (The Bumblezone)
• Sempiternal Sanctum Blue Suspicious (The Bumblezone)
• Sempiternal Sanctum Green Suspicious (The Bumblezone)
• Sempiternal Sanctum Purple Suspicious (The Bumblezone)
• Sempiternal Sanctum Red Suspicious (The Bumblezone)
• Sempiternal Sanctum White Suspicious (The Bumblezone)
• Sempiternal Sanctum Yellow Suspicious (The Bumblezone)

Given to you

• Cat Morning Gift
• Piglin Bartering