Tophzula

Tophzula is a Femslash ship between Azula and Toph Beifong in the Avatar: The Last Airbender series.

Canon
Toph and Azula were always enemies. Toph was a member of Team Avatar who was trying to help Aang bring an end to the war while Azula wanted to capture or even kill Aang. The two faced off at multiple points in time. Toph and Azula first really talked during the invasion of the Fire Nation. They were looking for Fire Lord Ozai and found Azula instead. Azula teased Toph for her blindness by announcing that she was rolling her eyes and Toph responded that she would roll Azula's entire head. Toph demanded information and revealed her lie detecting abilities only for Azula to reveal that she was a good enough liar to avoid lie detection. The group eventually escaped. Azula would later find the group again and attack them at the Western Air Temple, forcing Toph and the others to flee yet again.

Fanon
Tophzula has a decent amount of popularity in the Avatar fandom. It was mostly regarded as a "crack ship" for a while due to the fact that they were enemies and rarely interacted. A lot of fans tried to joke that Azula was the father of Lin when the Legend of Korra was announced. One of the creators, Bryan Konietzko, later got in on this joke and said that Azula was Lin's father. This started a huge meme and a lot of jokes in the fanbase. While Lin's father was eventually revealed late in the Legend of Korra, fans still enjoy pairing Toph with Azula to this day.

Trivia

 * Bryan Konietzko once joked that Azula was the father of Toph's daughter Lin.