Co-Writer is a robust software to provide word prediction, as well as text-to-speech, to support the writing process. The standalone app, with a one time cost, in iOS is a wonderful tool that can incorporate speech-to-text with Siri, with text-to-speech and word prediction built into the app. Additionally, topic dictionaries can be set to enhance the word prediction choices being provided in each document. Documents created in the app can be shared via email, messaging, and Google Drive. Co-Writer also has an app that works with a Co-Writer Universal subscription, allowing access to Co-Writer across platforms. Additionally, the Co-Writer Universal subscription allows of usage of the full featured third-party keyboard within any app on iOS devices including Google Apps. However, currently Siri is not available for dictation purposes when using the third-party keyboard. Co-Writer does have a Chrome extension as well as laptop based software.
Read&Write for iPad is available as a third party keyboard that allows for speakable word prediction and read back of text across apps and Safari content. The keyboard is clean and simple to use. The app is free, but there is an in app purchase to unlock all the features. However, currently Siri is not available for dictation purposes when using the third-party keyboard. Text Help has a Read and Write for Google extension as well as laptop based software.
Ginger is a cross platform free and premium grammar checker tool. Similar to Grammarly. I prefer Ginger as they have an iOS app. Both are available for Chrome and laptops. I find this tool useful for my own blog proofreading. Users can type right within the tool, or copy and paste text from other word processing tools to have it checked. It gives users a go to proofreader at any time.