The AI Anime Generator is a good place to start. It lets you create anime characters from text prompts, producing a broad range of results in a matter of seconds with high-resolution output. The service uses style-specific technology that knows about different anime styles, with an infinite variety of styles across many different genres. It's free to use, with output that's commercially allowed, so it's a good option for any creative project.
Another good option is Anime AI, which lets you create anime-style images from photos you upload. It offers a variety of styles like Naruto and Webtoon and lets you select specific attributes like skin tone or accessories. You can get a set of 100 custom images in a few minutes, making it a fast and relatively inexpensive way to generate anime images if you don't have technical expertise.
If you want a broader tool, check out Anime Art Studio. This free, web-based service gives you access to more than 100 stable diffusion anime models so you can create a lot of anime images, voices, videos and animations. It's got tools for image upscaling, voice generation and text-to-video, so it's a good option for those who want to create more involved anime content.