Two classic Legionnaires appear as contestants in the Galactic Games: Jo Nah of Rimbor, aka Ultra Boy, and Tenzil Kem of Bismoll ("Kem the Bismollian," misinterpreted in the closed captioning as "Camden Mismullion"), aka Matter-Eater Lad. Both characters are also referenced in the Legionnaire symbols which appear in the series' opening credits.
Interlac on a banner at the Galactic Games, shown just after Tenzil Kem's Flare Surfing 1st try, reads "Batman Lives".
Lightning Lad's brother Mekt, who he is competing against in the contests, would become a member of the Legion of Super-Villains in the comics and would use the name Lightning Lord.
The 'Standings" chart shown after the first race mis-spells Garth's name as "Lightnign Lad", followed by "Mekt Ranzz" who, in the comics, becomes Lightning Lord. They are followed by "Tarl", "Jo Nah" (Ultra Boy), Drake Burroughs (who becomes Wildfire in the comics), "Mota", and "Tenzil Kem" (Matter-Eater Lad).
When Superman and Phantom Girl "go out for snacks" they pass a Xuderian, the same species as Tomar-Re from the Green Lantern comics, movies, and TV show. Xuderians have gold skin, a cranial crest, and a beak. The same being, or another Xuderian, can be seen cheering from the top-most balcony immediately after Mekt wins the final event.