New cosmetics are leaked from every Fortnite update that requires downtime by data-miners. Some of these cosmetics have been released, but there are many yet to come. Here is a list of the unreleased Fortnite cosmetics.
Epic released new updates on a weekly basis and every week, a new item/weapon is added to Fortnite Battle Royale. In updates that require downtime, new files are added to the game and the majority of these files are leaked by data-miners when the update is available to download.
The most popular files to be leaked are the upcoming cosmetics, such as Fortnite skins, back blings, pickaxes, emotes/dances and more. The majority of these cosmetics will be available in the Item Shop, but some of them can be available as a part of an exclusive bundle, Starter Packs and Challenge rewards.
Here are all of the leaked cosmetics that have been leaked in past updates by data-miners, but have not been released in the game as yet.

FORTNITE LEAKED COSMETICS FROM V9.10

Bao Bros Skin/Outfit (Epic) – Steamed up and ready for action
Fortnite v9.10 Leaked Skin - Bao Bros
Fortnite v9.10 Leaked Skin – Bao Bros
Bao Basket (Epic) – Steamy and savoury
Fortnite v9.10 Leaked Back Bling - Bao Basket
Fortnite v9.10 Leaked Back Bling – Bao Basket
Souped Up (Uncommon) – Victory by the spoonful
Fortnite v9.10 Leaked Pickaxe - Souped Up
Fortnite v9.10 Leaked Pickaxe – Souped Up

FORTNITE LEAKED SKINS FROM V9.20

Airhead (Epic) – Pop into action.
Fortnite Leaked Skin From v9.20 - Airhead
Fortnite Leaked Skin From v9.20 – Airhead

Shot Caller (Rare) – It’s your move. Take your shot.
Fortnite Leaked Skin From v9.20 - Shot Caller
Fortnite Leaked Skin From v9.20 – Shot Caller
Breakpoint (Rare) – Disrupt. Distract. Dominate.
Fortnite Leaked Breakpoint Skin
Fortnite v9.20 Leaked Breakpoint Skin

FORTNITE LEAKED BACK BLINGS FROM V9.20

Utility Pack (Rare)  – Everything you need.
Fortnite Leaked Back Bling From v9.20 - Utlility Pack
Fortnite Leaked Back Bling From v9.20 – Utlility Pack
Signal Jammer (Rare) – Nothing gets through.
Fortnite Leaked Back Bling From v9.20 - Signal Jammer
Fortnite Leaked Back Bling From v9.20 – Signal Jammer

FORTNITE LEAKED PICKAXES FROM V9.20

Metro Machetes (Rare) – Street smart and impossibly sharp.
Fortnite Leaked Pickaxe From v9.20 - Metro Machetes
Fortnite Leaked Pickaxe From v9.20 – Metro Machetes

FORTNITE LEAKED SKINS FROM V9.30

Dare (Rare) – Dare to dream
Fortnite Leaked v9.30 Skin - Dare
Fortnite Leaked v9.30 Skin – Dare
Flutter (Rare) – Take flight
Fortnite Leaked v9.30 Skin - Flutter
Fortnite Leaked v9.30 Skin – Flutter
Pillar (Rare) – This isn’t even my final form
Fortnite Leaked v9.30 Skin - Pillar
Fortnite Leaked v9.30 Skin – Pillar

FORTNITE LEAKED BACK BLINGS FROM V9.30

Carapace (Rare) – Naturally thick skinned
Fortnite Leaked v9.30 Back Bling - Carapace
Fortnite Leaked v9.30 Back Bling – Carapace
Flutter Wings (Rare) – Float like a butterfly
Fortnite Leaked v9.30 Back Bling - Flutter Wings
Fortnite Leaked v9.30 Back Bling – Flutter Wings
Streamline (Rare) – Streamlined style
Fortnite Leaked v9.30 Back Bling - Streamline
Fortnite Leaked v9.30 Back Bling – Streamline

FORTNITE LEAKED PICKAXES FROM V9.30

Shard Sickle (Rare) – Harness the mysterious butterfly effect
Fortnite Leaked v9.30 Pickaxe - Shard Sickle
Fortnite Leaked v9.30 Pickaxe – Shard Sickle
Flycatcher (Uncommon) – Never cross a caterpillar
Fortnite Leaked v9.30 Pickaxe - Flycatcher
Fortnite Leaked v9.30 Pickaxe – Flycatcher

FORTNITE LEAKED EMOTES FROM V9.30

Featherweight (Uncommon) – Do you even lift?
Fortnite Leaked v9.30 Emote - Featherweight
Fortnite Leaked v9.30 Emote – Featherweight
Jumping Jacks (Uncommon) – Get jacked!
Fortnite Leaked v9.30 Emote - Jumping Jacks
Fortnite Leaked v9.30 Emote – Jumping Jacks

FORTNITE LEAKED WRAPS FROM V9.30

Blue Camo (Uncommon)
Fortnite Leaked v9.30 Wrap - Blue Camo
Fortnite Leaked v9.30 Wrap – Blue Cam
Scanline (Uncommon)
Fortnite Leaked v9.30 Wrap - Scanline
Fortnite Leaked v9.30 Wrap – Scanline
Which leaked cosmetics are you looking forward to the most?