Grammarly - Clear, effective, mistake-free writing everywhere you type.
Glosbe - Huge collaborative massively multilingual dictionary.
ProWritingAid - For the smarter writer. A grammar checker, style editor, and writing mentor in one package.
Visuwords - The fun and free way to look up definitions. THE graphical dictionary and visual thesaurus.
Gramara - AI grammar correction with transformers
Wordnik - the biggest online English dictionary, by number of words