Ideal GF (or ideal girlfriend) is an exploitable meme format featuring poorly drawn female figures, meant to depict all sorts of different types of girlfriends.
The initial purpose was to genuinely mirror the desires of men, but eventually the template has gained a sarcastic connotation by giving out the impression of men having comically unrealistic expectations towards women.
The template was first submitted on 4chan in 2016 by an anonymous user, who was requesting other anons to post their version of ideal GF under his image by using the format he created.
The post featured 4 types of girlfriends with a few individual personality traits attributed to them via text.
The exploitable format of ideal GF first circulated in communities of 4chan but eventually it has made it to Reddit by the end of 2016.
However, on Reddit it was mostly popular in the board /r/4chan, and the meme only gained major exposure after it went viral on Twitter in 2017.
Following that, almost every major social media site was covered with the format for a few months, but eventually the popularity has dropped and the ideal GF meme resorted to the boards of 4chan once again.