In the Christmas montage scene, they play chess (like Taylor-Joy did in The Queen's Gambit) and then play drums (like Teller's breakout role in Whiplash). This was in the script before Taylor-Joy and Teller were cast, and when the two of them wanted the scene removed, they were overruled by producers. Taylor-Joy went on to say that they were happy to be overruled, since people enjoyed it.
The bottom of the Gorge, as well as some creatures, are visually heavily inspired by the work of Polish painter Zdzislaw Beksinski.
In a brief background shot, the iconic Flame Towers of Baku, Azerbaijan, can be seen. Though the movie does not explicitly mention Baku, CGI was likely used to incorporate the towers into the cityscape, giving the scene a futuristic or exotic feel.
The Lithuanian word "Drasa" means "Courage". Though it is not a name, at least not knowingly given.