Grammarly - Clear, effective, mistake-free writing everywhere you type.
Artha - Artha is a handy thesaurus based on WordNet with distinct features like global hotkey look-up...
Deep Grammar - Grammar checker based on deep learning
WordWeb - One-click lookup in any almost any Windows program; Hundreds of thousands of definitions and synonyms; The latest international English words; Works offline, or reference to Wikipedia and web references.
Boost Editor - The AI your content can’t live without
GoldenDict - The program has the following features: Use of WebKit for an accurate articles' representation, complete with all formatting, colors, images and links.