For sci-fi stuff, it's all about Isil.
Studio Skye is also good. That is my main go to for landscaping items, like trees, dirt roads and that sort of thing.
For clothing: By Swirly, Really Rockabilly, Set to Stun, the Secret Store, Belle Epoque, Zenith, R2. Also Addams and Blueberry
Hair: Magika, Elua, Truth, Doux, Exile
Home, decor: FIN/Relive the 50s, What Next, Dysfunctional Designs, % ( yes, it's "percent" as the symbol. )