El Susurro is a Resolver nail gun that is silent when it fires and when it hits. It is one of the best stealth weapons in Far Cry 6, and you can buy it from Juan once you reach rank 5.
It is a quiet killer for base infiltration. Shots make no sound and impacts make no sound either. Hide bodies or pick targets out of sight of others, since a found body can still raise the alarm.
Reach rank 5, Cabo, then buy it from Juan with Depleted Uranium.
You can swap to Sustained Pressure for a bigger magazine, a Quick Compressor and an Extended Nail Coil.
If you lack a good sniper rifle, El Susurro makes a decent stand-in at mid range. Past that range, the nail drop makes a suppressed rifle the better choice.
Auto-Crossbow
The Auto-Crossbow, called the Executioner in Far Cry 6, is a semi-automatic crossbow you carry as a special weapon. It returns from Far Cry 4 and looks like a stockless BZ19 with a helical magazine.
Auto-Turret
The Auto-Turret is a deployable gadget that you place and then leave to shoot enemies on its own. It is handy for guarding a flank, and FND Engineers use their own turrets against you.
Compound Bow
The Compound Bow is a silent bow for stealth kills and hunting in Far Cry 6. Arrows make no noise, so you can drop guards without alerting a base, and its unique version is the brightly painted Bullseye.
Image: UbisoftDiscos Locos
Discos Locos is a Resolver weapon that launches CDs as blades while it plays salsa music. Hip-fire shatters discs into shotgun-style shrapnel and aimed fire throws them whole, so it works at close and mid range.