Artbreeder

Artbreeder, formerly known as Ganbreeder, is a collaborative, machine learning-based art website. Using the models StyleGAN and BigGAN, the app allows users to generate and modify images of faces, landscapes, and paintings, among other categories. 
The site was popularized through the spread of viral images created using the website, most notably with various realistic restorations of the faces of historical figures. 
Overview.
On Artbreeder, users mainly interact through the remixing - referred to as 'breeding' - of other users' images found in the publicly accessible database of images. The creation of new variations can be done by tweaking sliders on an image's page, known as 'genes,' which in the 'Portraits' model can range from color balance to gender, facial hair, and glasses. Additionally, any image can be 'crossbred' with other publicly viewable images from the database, using a slider to control how much of each image should influence the resulting 'child'.
New images can also be uploaded to certain categories, but the amount of uploads each month is heavily limited for free users, and each upload can take "up to an hour" due to heavy load on the website's computing resources. 
Excluding the 'Anime Portraits' model, any two images from the same category can also be interpolated between in animated video form. For free users, there are limits on how a user's number of high-resolution downloads and animations, but these limits are loosened for paid users, and removed entirely for the highest-paying tier.
Notable usages.
The similarly AI-driven text adventure game AI Dungeon uses Artbreeder to generate profile pictures for its users.
In May 2020, Dutch digital artist Bas Uterwijk began using Artbreeder to create realistic recreations of various historical figures, drawing coverage from several news outlets. Later the same year, Canadian VR specialist Daniel Voshart drew similar attention for his restoration of the visages of several Roman emperors using Artbreeder. Writer Giacomo Lee praised the results as "remarkably polished and authentic," noting that the images brought AI into the conversation around digital art. 
Reception.
Since its launch in 2018, Artbreeder has been praised for its "radically simplified" workflow and freemium business model, which made the technology of GANs accessible to a larger demographic of internet users. Vlad Alex of Towards Data Science described Artbreeder's "transformative art generation" as "a genuinely new way of re-mapping our reality." He also praised the "dynamic" development, noting that then-solo developer Joel Simon "reacts quickly to users’ ideas and corrections."
The artwork generated by users of the website has been described as "beautiful" and "surreal," drawing comparisons to "weird, incomprehensible dreams" that "somehow touch the deep, unconscious parts of [the] mind". Writer Giacomo Lee especially praised the landscapes, calling the results "very impressive." However, the faces on the website drew Lee's criticism for looking "creepy and 'off,'" and still nowhere near the quality attained by actual digital artists. 
Additionally, the site faced criticism for perceived confusing aspects of the AI's behavior. Jonathan Bartlett of Mind Matters News noted that "As is always the case with AI, sometimes the [gene] knobs don’t work as expected and sometimes the results are… strange," while conceding that Artbreeder was still "probably the start of a new future of made-to-order stock images." Writers from "Hyperallergic" also took issue with perceived racial biases in the Portraits model, citing a comment from a user who faced difficulty from the neural network while attempting to darken the skin of a portrait to match a source image.