In the Fate series, there is an abundant (some would say blatant) proliferation of characters who look nearly identical to each other, but can either hail from parallel universes, and/or be summoned into a variety of Servant classes, and/or become Alter or Lily Servants, and/or have alter egos of themselves split off and become individuals of their own. Since the Fate universe (and the Nasuverse as a whole) involves alternate universes that promote an impossibly huge variety of character interactions, some of these characters have become notoriously egregious for the sheer amount of variants they have. Fans have colloquially added the '-face' suffix after a character's name to indicate this.
The three main heroines of Fate/Stay Night - Saber, Tohsaka Rin, and Matou Sakura - are popular characters which utilize this trend, and their variants are all referred to as the umbrella terms Saberface, Rinface, and Sakuraface respectively. There are plenty of other characters who are involved in this phenomenon as well, such as Elizabeth Bathory, Tamamo no Mae, Nero Claudius, and Jeanne d'Arc (the latter two are also regarded as Saberfaces due to their uncanny resemblance to Artoria). While this is usually subjected to females, some males have begun joining the tend as well due to Fate/Grand Order, such as Archer, Cu Chulainn, and Gilgamesh.
This pool is for images that demonstrate the hilarious number of variants that a character has, sometimes poking fun at how the Fate series has begun to lack in creativity. The recommended minimum is five variants in a single image, although four is fine if the character only has that many.