If you're looking for a Kerlig alternative, Reword is definitely worth a look. Reword gives you a personalized writing assistant trained on your writing style, along with Cowriter for coauthoring, Voices to keep your writing voice intact, and SEO Optimization. It supports more than 25 languages and integrates with common content management systems, so it can be useful for anyone who wants to improve writing quality and productivity.
Another good option is QuillBot, which offers a range of writing tools. QuillBot has a paraphraser, grammar checker, plagiarism checker, summarizer and translator. It's designed to help you work faster while producing high-quality work, with features like unlimited paraphrasing and advanced grammar suggestions in its Premium subscription.
If you're looking for a more general-purpose writing assistant, you might want to check out HyperWrite. HyperWrite has a range of tools to help you, including Flexible AutoWrite, Summarizer and AI Speech Writer. It also can help you with research as you write and learn your writing style to help you write more quickly, and it's good for students, freelancers, academics and businesses.
Last, CoWriter offers editing help, citations and content creation that sounds like you. With tools like AI-powered autocompletion, citation formatting and collaboration tools, it's good for academic research, content creation, technical writing and business communications. Its pricing tiers, including a free version, means it can be used for a variety of needs and budgets.