Balmorra recently reappeared with an on-screen namedrop in Episode 14 of the Bad Batch, Season 2, with an Imperial Scientist incarcerating Clones from the planet. SWTOR players will recognise Balmorra as it featured heavily in the Vanilla game as one of SWTOR’s only single-faction chronological story planets with a deep tie to the Colicoid species from Legends Canon, from which the Droideka model expanded it’s backstory from.

However Balmorra was not created new for SWTOR, in fact it dates back to the mid 90s ‘Dark Empire Trilogy‘ for Star Wars, appearing as the first major story location in Dark Empire 2, a sequel to the infamous Dark Empire Trilogy that teased us with Luke falling to the Dark Side as well as the first return of Emperor Palpatine in a host body decades before it would be repeated in the new Sequel Trilogy.
This would not be Balmorra’s only appearance between the 90s Novel and SWTOR, as the planet both featured as passing name-cameos in early Season 1 Clone Wars episodes as well as referenced prominently throughout the 2001 New Jedi Order novel series.

While it was most prominently seen in SWTOR, Balmorra would only be referenced sparsely in official canon until this Bad Batch episode, with it only being referenced in Season 1 of the Clone Wars as well as a small location in the Force Awakens official tabletop RPG.
Unfortunately while Colicoids are officially canon as well, they have yet to be linked to Balmorra or Balmorran Arms as they were in the old Legends Canon & SWTOR.