One of Adora and Catra's fellow recruits is called Lonnie. This is a reference to the character 'Lohni' from Friendship (1985) who had been Adora's best friend and second in command during her time in the Horde.
The Etherian villages of Thaymore and Elberon were mentioned. Thaymore was first seen when Prince Adam visited Etheria for the first time in He-Man and She-Ra: The Secret of the Sword (1985) and Elberon was where She-Ra met Sorrowful the dragon in The Laughing Dragon (1985).
The Masters of the Universe Classics line which began in 2008 revealed Bow's real name to be Kyle Reccula. In this series, Kyle is a separate character who is part of the Horde.
The Sword parts 1 and 2 were adapted into a storybook by Tracey West titled "Origin of a Hero" that was released on April 30, 2019. It features a couple of extra chapters to introduce the characters, and the name of the minor Horde 'Sergeant' is revealed to be 'Cobalt'.