I lost a lot of weight last year and suddenly became interested in clothes again. I browsed lots of Style & Beauty threads, and looked up every brand that was mentioned. Once I got a sense of what I liked, I searched for those brands on Vinted. I now have a whole new wardrobe of stylish clothes which are more fashion-forward than the stuff I used to wear.
Some brands to start you off - Kemi Telford, Rixo, Pink City Prints, COS, & Other Stories, Sézane, Farm Rio, You Must Create, Me & Em, Saloni, Shrimps, Sessun, Erdem, Poetry, Toast, Self-Portrait, The Fold, Tara Jarmon, Gerard Darel, Kitri, Fabienne Chapot, Odd Molly, Palava, Aspiga, Theory, Damson Madder, Joseph, Maje, Isabel Marant, Diane von Furstenberg, Nicole Farhi, Margaret Howell, Rouje, Stine Goya, Arket, Staud, and Wyse. Just have a look and get a sense as to what you love, what you like, and what's not for you. And while you're getting the hang of your new style, I'd buy second-hand where you can.