The ones on the Harry Potter Shop are by Rubie's. IDK why they don't put the manufacturer's info on the page.
https://www.rubies.com/licensed-themes/harry-potter-costumes/replica-adult-gryffindor-robe.html
If you don't live in America (Universal's shipping costs are ridiculous!) I'd probably recommend Cinereplicas' robes. Only downside is the Gryffindor colours are more wine-coloured.
Okey thanks i really appreciate your help https://www.amazon.com/FUji-Shiro-Sailor-Cosplay-Costume/dp/B01IZ7CJSU/ref=sr_1_2?ie=UTF8&qid=1518650456&sr=8-2&keywords=no+game+no+life+shiro+cosplay
Not sure if decent but at least it's not phallic like the other suggestions : https://www.amazon.ca/Rubies-Costume-Diamond-Headed-Black/dp/B0020017V4/ref=sr_1_1?ie=UTF8&qid=1517214073&sr=8-1&keywords=pimp+cane
MLP sleepwear?
The only thing that comes to mind is this: https://www.amazon.com/My-Little-Pony-Rainbow-Kigurumi/dp/B00DZX62BK
I was kinda bummed out that they only had a RD one though, and the overall quality isn't quite as good as kigus from Japan/China but oh well.
Atleast it's official MLP merch though.
https://www.amazon.com/InCharacter-Costumes-Womens-Indian-Costume/dp/B0050ALJDC
These are okay in your book?
That just did turn an entire group of people with a rich culture into a costume based on stereotypes.
And the idea that women have to dress as slutty as they can get away on Halloween is kind of odd when you look at it from a sense of perspective.
As a guy, I don't really have to do that. I don't have present my body at all. I can be a ninja turtle. I never have to be a sexy ninja turtle.
I bought this Shintaro hoodie and would not recommend it. It's a typical import cosplay item - it looks like the picture, and it fits, but it is not a good quality hoodie. Very cheap production, very cheap material.
Most import cosplay sites will be the same. They'll get you the product and it will look like the picture, but it won't be a good quality wearable item.
You could try to find an etsy shop that would do it on commission. It'd definitely be more work, and more expensive, but you'd be much more certain of a good quality piece of clothing at the end of the day.
Edit: Meant to add, while it's not the same as the one you linked in your picture, it's a related experience because it was buying an import cosplay item.