!!Trivia for ''Gold'', ''Silver'', and ''Crystal'':
* CowboyBebopAtHisComputer: For months prior to the official release of the game promotional materials referred to the pokémon Marill as "Pikablu" likely due to its mouse-like appearance and... well, [[ShapedLikeItself the fact that it was blue]]. Marill was ''never'' officially referred to by this name at any point, not even during the planning stages. Despite this the misnaming was so prevalent that even Topps used it in the ''Anime/PokemonTheFirstMovie'' [[http://bulbapedia.bulbagarden.net/wiki/Pok%C3%A9mon_the_First_Movie_Trading_Cards Trading Cards]].
* GodNeverSaidThat: Marill is very frequently treated as a Pikaclone by the fandom. While the parallels are there, Game Freak has never officially promoted Marill's line in that capacity, and the association is a leftover from the old "Pikablu" rumors.
* FanNickname: Silver (the Rival, not the game) is sometimes jokingly referred to as [[MyNameIsQuestionMark ???]].
* SerendipityWritesThePlot:
** The limited space of Game Boy Color cartridges is more than likely the reason that many buildings and dungeons in Kanto have been scaled down or became inaccessible due to various plot reasons in Kanto. For example, [[spoiler: Cinnabar Island erupted]], Fuchsia City & Cerulean City's shared music was replaced with that of Celadon City and Viridian City, respectively, and most of Silph Co. isn't open to the public.
** Some of these elements were brought back in the remakes. The music issues are solved for both the aforementioned towns. Other locations (e.g. Routes 24 and 25, Cinnabar Island, and Viridian Forest) become their own areas once again, Cerulean Cave returns, and the Seafoam Islands are changed from having a single room to a fully fledged Gym. Some buildings that were closed in the original games are now open again and offer new services: the Pewter Museum can revive fossils, and the former Safari Zone complex in Fuschia City is re-opened as the Pal Park.
* WhatCouldHaveBeen:
** In an early build of the game, the name of the starting town wasn't New Bark Town, but {{Silent Hill}}s.
** The Lake of Rage was originally going to have its own town, complete with a Gym. The ability to [[WarpWhistle Fly]] there may be a holdover from this.
** Pre-release material promised a skateboard item (separate from the bike) that would be allow access to new areas.
** [[http://bulbapedia.bulbagarden.net/wiki/File:MicroGroup_Game_Review_Volume_14.jpg This image]] from the magazine ''[=MicroGroup=] Game Review'' shows unused designs for 2 Pokémon; a turtle that resembles [[VideoGame/PokemonBlackAndWhite Tirtouga]] and what can only be described as a Hitmontop and Clefairy hybrid. It also shows that Tyranitar going to be brown instead of green.
** [[http://bulbapedia.bulbagarden.net/wiki/Prototype_Pok%C3%A9mon_and_characters#Kurusu The original Water and Fire starters were completely different creatures.]]
** A string of text in the [=ROM=] suggests that the Honey Tree mechanic from VideoGame/PokemonDiamondAndPearl was originally intended for these games.
* WorkingTitle: ''[[NumberedSequels Pocket Monsters 2]]: Gold and Silver'' for ''Gold and Silver Versions''; ''[[HilariousInHindsight Poké]][[NamesTheSame mon]] [[VideoGame/PokemonXAndY X]]'' for ''Crystal Version''.

!!Trivia for ''[=HeartGold=]'' and ''[=SoulSilver=]'':
* WhatCouldHaveBeen: An unused [=PokéGear=] icon that resembles Kris can be found in the data, implying she might have been considered to appear in some capacity at one point.