I literally just came here to ask the same question and your thread was at the top. only one available on Amazon with mixed reviews.
I just want a very light thin rear she'll that covers the whole thing
Box wave had a really inexpensive one Flr the original sir that while not rigid was lighter than the smart case cover made by Kayscase
I'd go with a skin but for the fact I very occasionally use a full case for the stand function and travel.
In home I much prefer the tempered glass protector and a thin rear case.
I checked mono price - nothing there...
I'm going to check fast tech - shipping would take ten days but they're cheap
Fast tech does have some for $5.50 plaid multiple colors available
https://m.fasttech.com/products/0/10012910/2174801-protective-tpu-plaid-back-case-for-ipad-air-2
If you don't know them, yes they're fine to order from, I've done so many times. Shipping takes 10-14 days and returns have to be approved and sent back to Florida, where you upload a copy of the receipt and get reimbursed. It's not exactly simple to return stuff but most of the items I've received are as represented.
I ordered a black one. I'll post back.
They also have a knockoff of the really expensive air vent holder. I've forgotten the name. I own the original and bought s replica of that too. The original is $30 replica $4