AIWritingPal is a good option, with a clean interface for producing high-quality content fast. It supports more than 30 languages and can fix grammar and spelling with AI-powered suggestions. The tool also offers other writing tools like article and blog idea generation and marketing and advertising help. With a free plan and a premium plan for $29.99 per year, it's got a good balance of options and features.
Another good option is ChatGPT Writer, which is geared specifically to help you draft emails and messages. It supports all languages and offers grammar checking, rewriting, translation, summarization and brainstorming. With tight integration with Gmail and strong security, it's a good option that's easy to use, with prices ranging from free to $349 per year.
If you want something you can use on a pay-as-you-go basis, Simpler is a good option. It offers AI-continued writing, a distraction-free editor and Grammarly spellchecking. It's trained on a large portion of the internet, so it works well in many languages. With a one-minute setup process and a starting price of just $1, it's a good option if you want to get your words out quickly.
Last, Auri offers a full-featured productivity suite with a multilingual AI Keyboard for writing, translation and grammar checking. It also offers voice dictation and a variety of features for organizing and converting notes. It's available on iPhone, iPad, Mac and Apple Watch. Auri offers both free and Pro versions, with daily limits on the free version and unlimited use starting at $9.99 per month.