Stream UI Kit - A beautiful open source Bootstrap 4 UI kit
Sortd - Rated the #1 App for Gmail
iOS Starter Pack - A bundle of beautiful, functional iOS apps built with SwiftUI to get you started.Includes the Xcode projects and SwiftUI code for the Shop App, Finance App, and Social App.
KanbanMail - A Kanban board for your emails.
Rainbow UI Kit by EpicPxls - A colorful Bootstrap 4 UI Kit for landing pages
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.