Playground AI
Playground AI is a free-to-use online AI image creator. This is a quick overview of this tool, its features, benefits, and limitations.
The tool consists of two parts—a feed of images generated by different users along with the prompts they use:

and AI image creator:

Playground AI image generator features
The core set of features that Playground AI offers is similar to other AI image creators. At the left panel, you can see Prompt, which allows you to specify what you want to visualize, and at the right panel, Model that will be used to visualize the prompt. By default, Playground uses Stable Diffusion 1.5 model, which is the best option for anyone who just starts using AI image generators, but you can change it to Stable Diffusion 2.1 or Dallee-2 (note that the Dalle-2 model requires a Pro plan).
The tool can generate images in different dimensions. By default, Image Dimensions are set to 512 x 512, which is optimal for Stable Diffusion 1.5.
Playground also offers Prompt Guidance, which allows you to specify how close the image generated by AI should be to your prompt, and Quiality & Details, which is basically a different name for the number of steps that AI model uses to produce the Image (the more steps the AI engine takes, the higher number of details the Image will have but the more it will take to generate the Image).

It's also possible to provide an image as a source for the AI using Image to image generation. Unlike other tools, you can draw the image you want to submit to the Playground inside the editor.

Advanced features that Playground offers
Playground offers a few cool features that can potentially make this tool more attractive to AI artists. The first one is Remove From Image, which allows you to specify things you don't want to see in the generated image. AI image generators are notoriously known for adding unnecessary visual noise, such as extra fingers on human hands or decorative blur, and this setting allows you to get rid of it.

Filters are another neat feature that Playground offers to its users. You can choose a particular style for your image, and the tool will modify the prompt based on your selection to generate the image in that specific style.

Private session allows you to make the AI-generated images visible only for you.

The generated image also has a series of contextual actions that you can use. The most helpful are Face Restoration which allows you to fix human faces generated by AI, and Upscale by 4x (this setting is valuable if you want to use generated images in your design).

Playground pricing plans and limitations
Playground offers a Free and Pro plan. Free plan allows you to make up to 1,000 images every 24 hours, which is more than enough for most AI artists. But the Free plan only supports Stable Diffusion, not Dall-E 2, so if you want to use Dall-E, you should go for the Pro plan ($15/month) that will allow you to create 2,000 images per day.
While I used the tool, the safety filter triggered quite often, even for the super safe prompts like "cute cat." And right now, there is no way to turn off the safety filter which can be frustrating for many people.