When I think of fast fashion brands, I can't help but think of 'The Big Five' of wild animals in Africa. In case you're not familiar with the big five, it is a term coined to reference the difficulty in hunting the lion, leopard, black rhino, African bush elephant, and the African buffalo. Of course, we (meaning I) don't support the hunting/poaching or anything of that sort of any animals, however it is now widely used by safari tour operators (which I have done once before and it was utterly amazing), so I don't mind using the analogy.
Why do I think of this when I think of fast fashion brands? Well, the first brands that come to mind happen to be the big top fast fashion businesses, which are; Forever21, H&M, Zara, SHEIN, and URBN. Of course, there are far far more than just these, namely Fashion Nova, Boohoo, Topshop, Primark, Missguided, New Look, and Uniqlo, but for the sake of this analogy, I'm going to limit it to these five major fashion brands.
Disclaimer: These are in no way in order of worst to best or best to worst!