Interfaces.pro is described as 'Brand-focused collection of inspirational UI design examples updated on a weekly basis. Desktop and mobile modes, multiple categories and dozens of brands (Intercom, Stripe, Google and more)'. There are four alternatives to Interfaces.pro, not only websites but also apps for SaaS. The best alternative is Flomo Design, which is free. Other great sites and apps similar to Interfaces.pro are foxyapps (Free), pttrns (Free) and UI Sources (Freemium).
Foxyapps is a curated collection of best-designed real-world Android and iOS mobile apps. Whether you're looking for great design inspiration, learning the best UX and UI practices, or just like discovering new hot apps.