Below is a list of all back blings and how they can/could be obtained.
Hive Store Back Blings
The following back blings can currently be purchased from the Hive Store:

Can be purchased on the Hive Store.
Rarity: Rare

Can be purchased on the Hive Store.
Rarity: Epic

Can be purchased on the Hive Store.
Rarity: Epic

Can be purchased on the Hive Store.
Rarity: Epic

Can be purchased on the Hive Store.
Rarity: Epic

Can be purchased on the Hive Store.
Rarity: Epic

Can be purchased on the Hive Store.
Rarity: Epic

Can be purchased on the Hive Store.
Rarity: Epic

Can be purchased on the Hive Store.
Rarity: Rare

Can be purchased on the Hive Store.
Rarity: Epic

Can be purchased on the Hive Store.
Rarity: Legendary
Unobtainable Back Blings
The following back blings are not currently obtainable:

Obtained by purchasing a limited edition Endolotl plushie from Makeship.
Rarity: Legendary

Could be obtained during April Fool's Day 2024.
Rarity: Legendary

Obtained by purchasing the 2024 Winter Ticket on the Hive Store.
Rarity: Epic

Obtained by purchasing the 2024 Winter Ticket on the Hive Store and completing a special quest.
Rarity: Legendary

Obtained by purchasing the Valentine's Gift Bundle or being gifted by another player.
Rarity: Epic