One of the theories about why 4Kids Entertainment went for a Gag Dub is that they weren't that interested in the show itself, but there was reference to the Ultra Series in Kirby: Right Back at Ya! that viewers wouldn't get unless they had seen one of the shows before. That's right; 4Kids may have acquired Ultraman Tiga for the sole purpose of explaining a joke in another series.
Acting for Two: Hiroshi Nagano plays both Daigo and an errand boy/intern named Nagano in episode 49.
Contest Winner Cameo: Taraban was the winner of a Create Your Own Monster contest held by Tsuburaya Productions.
Silvergon was created from Sealizar, with added parts from Gagi.
Goldras was remade into Yanakagi.
Recycled Script: Akio Jissoji based episode 40 "Dream" off an unused Ultra Q script he wrote 30 years ago. The main difference is that the Monster of the Week would have been more like the mythological baku rather than the bizarre chimera that is Bakugon.
Tiga's Protector was intended to be removable and be used just like the Eye Slugger. It's unknown exactly why this idea was dropped.
Golza was originally going to be named Orgo.
Episode 23 (the one with the Weaponizers) would have originally had a major revelation that many of the monsters fought by Tiga were creations by a scientist from the ancient civilization he protected. While the idea was dropped in the end, the "ancient scientist" idea was recycled for episode 45 (Gijera) with the character of Nook.
You Look Familiar: Alien Muzan's human form actor later played that of Hudra (and voiced him) in The Final Odyssey