who to avoid:

these brands are making "no concrete effort for people, the planet, or animals across the supply chain and are notorious for poor quality clothing that often ends up in the landfill after a few years":

• shein
• missguided
• nasty gal
• boohoo
• pretty little thing
• forever 21
• hot topic
• fashion nova
• zaful
• savage x fenty

these brands lack transparency as they provide "no publicly available information on their production":

• havaianas
• crocs
• romwe
• brandy melville
• skims
• kendall + kylie
• cider
• le coq sportif
• showpo
• victoria beckham

source: https://goodonyou.eco/best-worst-rated-brands-2021/

what to do instead? if possible, do not buy from these companies. in general, it is best to avoid fast fashion chain stores, esp. if they are very cheap. if you need to buy cheap, the best thing you can do to be eco-friendly, is buy second-hand, esp. from charities! these are usually so much cheaper than buying from chain stores anyway! - and btw, you can get some seriously good quality, beautiful items from charity shopping. keep in mind that some have online websites you can buy from, like oxfam. visiting charity shops in person does tend to be cheaper though, in my experience.

apart from charity stores, you can buy second hand through apps like vinted, depop, etc. i use vinted and it's super easy.