In Pokémon Mystery Dungeon, there are hold-items called scarves that increase statistics or make the Pokémon immune to certain status conditions when held. These are sometimes referred to as bands.

Lists

Bands/Scarves that prevent status conditions

Loud Band

Sleep effects end earlier.

No-Stick Cap

A hold item that prevents the Pokémon's items from becoming sticky and gummed up.

Pecha Scarf

A hold item that prevents the Pokémon from being poisoned or badly poisoned.

Persim Band

A hold item that prevents the Pokémon from becoming confused.

Weather Band

A hold item that prevents the Pokémon from feeling the effects of the weather.

Bands/Scarves that promote stats

Blue Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a blue aura.

Brown Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a brown aura.

Cobalt Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a cobalt aura.

Def. Scarf

A hold item that boosts the Pokémon's Defense.

Detect Band

Raises evasiveness.

Fuchsia Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with fuchsia aura.

Green Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a green aura.

Lime Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a lime aura.

Minty Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a minty aura.

Munch Belt

This item has its own article, found here.

Orange Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a orange aura.

Pink Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a pink aura.

Power Band

A hold item that boosts the Pokémon's Attack.

Purple Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a purple aura.

Red Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a red aura.

Silver Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a silver aura.

Sky Blue Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a sky blue aura.

Special Band

A hold item that boosts the Pokémon's Special Attack.

Twist Band

Prevents Attack and Special Attack from being lowered.

Violet Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a violet aura.

Viridian Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a viridian aura.

Yellow Bow

Slightly boosts Attack, Defense, Special Attack, and Special Defense for users with a yellow aura.

Zinc Band

A hold item that boosts the Pokémon's Special Defense.

Other Bands/Scarves

Beauty Scarf

Evolves Feebas into Milotic

Bounce Band

A hold item that makes thrown items bounce off the Pokémon.

Curve Band

Tossed items can take a curved path

Customer Scarf

Pokémon hurt by confused party members will experience drop in hunger rather than in HP.

Diet Ribbon

When held by a partner, the partner is not able to move. If the leader holds it, its Belly goes down faster.

Dodge Scarf

Prevents user from being damaged by tossed items.

Friend Bow

Increases chance of recruiting wild Pokémon when held by leader.

Gold Ribbon

No effect in dungeons, but sells for 2000 Poké. Can be bought for 4000 Poké.

Heal Ribbon

A hold item that speeds up the Pokémon's natural HP regeneration. The Pokémon's Belly will go down faster, however.

Hunger Ribbon

Hunger decreases faster when eating food.

Joy Ribbon

A hold item that earns the Pokémon 5 Exp. Points when taking any kind of damage.

Mobile Scarf

Enables the user to walk through walls. However, the belly goes down faster when walking through walls.

Pass Scarf

A hold item that can enable the Pokémon to pass off the effect of attacks and certain kinds of hostile moves to a Pokémon next to it. However, it also makes the Pokémon's Belly go down.

Patsy Band

Increases the user's chance of taking critical hits from enemy moves or attacks.

Pierce Band

Makes the user's thrown items pierce through all targets, walls, and obstacles without stopping.

Plain Ribbon

No effect.

Racket Band

Awakens every Pokémon in room.

Sneak Scarf

Prevents the user from waking up enemies that are asleep from the start of the floor.

Stamina Band

Hunger decreases more slowly.

Stealth Scarf

Prevents sleeping wild Pokémon from awakening.

Stern Band

Hunger depletes slower, but doesn't work in walls.

Through Band

Tossed items continue through foes.

Tight Belt

Prevents the user from getting hungry unless the holder walks through a wall or uses a linked move.

Trap Scarf

Prevents traps from activating when the user steps on one.

Warp Scarf

User randomly warps around the map.

This item article is part of Project ItemDex, a Bulbapedia project that aims to write comprehensive articles on all items.