Datamining of the the latest patch (v4.2.0) reveals some of the cosmetics we should expect to see over the coming weeks including outfits, gliders, pickaxes and back bling:

Update: Names and rarities added thanks to Storm Shield One.

Toxic Trooper (Epic) and Hazard Agent (Epic)

Venturion (Epic) and Moisty Merman (Legendary)

Bandolier (Epic) and Director’s Cut (Rare)

Airfoil (Rare) and Autocleave (Rare)

Stop Axe (Rare) and Meltdown (Uncommon)

Triumph (Uncommon) and Mertank (Legendary)

Contagion (Epic) and Pathogen (Epic)

Emotes (Rarities as coloured)