The starfish-like creature in the Preserver's collection is Starro the Conqueror, a galactic villain who was the very first foe of the Justice League of America in their introduction story in DC's "The Brave and the Bold" #28 (Feb-Mar, 1960).
The Preserver may be inspired by the Collector (Taneleer Tivan) from Marvel Comics, who also caged rare species for his gallery.
Sherman Howard, who voices the Preserver, played a college-age Lex Luthor in Superboy (1988) beginning in season 2.
The voice artist for Sqweek David L Lander played a character named Squiggy on Laverne and Shirley. Seems that is where the name came from.
Lobo made his live-action debut in the second-season premiere of Krypton (2018), as a secondary antagonist of Superman's grandfather, Seg-El. A Lobo spin-off was planned, but ultimately scrapped following the announcement of "Krypton"'s cancellation.