Alphyne

Alphyne is the femslash ship between Alphys and Undyne from Undertale.

Canon
The first hint of Alphyne is during Mettaton's Quiz Show when Mettaton asks who Alphys has a crush on and the player answers Undyne. The answer shows up as correct (this also happens if the player chooses Asgore or the human).

Afterwards, if the player is on a True Pacifist Route, Undyne asks Frisk (the human) to deliver a letter to Alphys. Frisk does that, but Alphys assumes the letter is from the human so the two go on a date. Undyne interrupts the date and Alphys says that she and Frisk were practicing. Undyne and Alphys end up together after the date.

In the credits of the Pacifist Route, Undyne kisses Alphys.