Sitecake - Drag and drop CMS for HTML websites. It's flat file CMS so it's pretty fast.
Crowdin - Localize your product in a seamless way
Anchor CMS - Free and lightweight blogging system
POEditor - The translation and localization management platform that's easy to use *and* affordable!
Textpattern - Textpattern is an elegant content management system that is free, open source software.
Lokalise - Localization tool for software developers. Web-based collaborative multi-platform editor, API/CLI, numerous plugins, iOS and Android SDK.