Alas, I can't access up-to-date databases or specific document collections to provide current or exclusive information on particular fonts including "GoodCityModern Plain" by Altsys Metamorphosis. But, let me give you some context and characteristics generally associated with the type of font you're curious about, based on the information in the name and common knowledge up to my last update in 2023.

"GoodCityModern Plain" carries a name that evokes a sense of contemporary urban sophistication mingled with classic touches, seemingly designed for clarity and readability while also catering to modern aesthetic sensibilities. The term "Plain" within its name suggests a straightforward, unembellished style, focusing on functionality and ease of use in various applications, from digital design to print media.

Altsys Metamorphosis, known for its role in the development of early graphic design software and font technology, suggests a pedigree of innovation and quality. Fonts produced under such auspices would typically combine technical precision with creative design, allowing for versatility across a wide range of projects.

Given its modern and plain characteristics, GoodCityModern Plain likely features clean lines, uniformity in stroke width, and a balanced proportion, making it an excellent choice for body text that requires both readability and a modern aesthetic. It's probably well-suited for professional documents, web design, and user interfaces where clarity of information is paramount. The font might also carry certain minimalistic traits, making it adaptable to branding and signage that demand a modern and sophisticated touch.

In terms of design application, such a font would be a go-to choice for projects that require a blend of contemporary look and timeless elegance, functioning well in both print materials like brochures and reports, and digital formats including websites and mobile apps.

While I can't provide specific details on "GoodCityModern Plain" by Altsys Metamorphosis, I hope this gives a satisfying glimpse into the likely characteristics and applications of a font with such a name and heritage. In your quest for detailed specifications or licensing information, I'd recommend checking with reputable font libraries or directly reaching out to the creators, if possible.