Letsview: A free screen-projection tool, which can be used to screen computers and mobile phones and control the computer

Letsview is a free cross-platform screen projection tool, with Windows, macOS, iOS, Android, Android TV client, support AirPlay, Miracast, DLNA protocol, can screen projection between mobile phone and computer, also can control Windows computer through App. The phone is projected

Evernote's powerful alternative: Joplin, an open source encrypted notebook

Due to the demand of universality, notes application is a topic for a long time, but due to the differences of demand, to create numerous similar services and software, if there is such a subdivision demand: open source, cross platform