There will eventually be at least one Pokemon (or line of Pokemon) for every type combo, including those that don't yet exist in canon
As of Version 4.0, four out of the nine unused type combinations in canon have been used in Radical Red: Fire/Fairy (Galarian Ponyta line), Fairy/Ground (Seviian Milotic), Bug/Dragon (Seviian Lokix), and Rock/Ghost (Seviian Noibat line). With this in mind, it wouldn't be too much of a stretch for the developers to either retcon a couple more Pokemon or add a couple more Seviian forms to make all 171 type combinations appear in this game. Here are some ideas for the final five type combos:- Bug/Normal: Retconned Kricketot and Kricketune (they'd likely be part Sound-type if said type existed, and Normal-type moves tend to be sound-based).
- Rock/Normal: Retconned Rockruff and Lycanroc
- Ice/Normal: Retconned Cubchoo or Alolan Vulpix
- Steel/Normal: Retconned Meltan
- Ice/Poison: Seviian Cloyster (with Seviian Shelder being Water/Poison)
More potential type retcons
Quite a few type retcons occurred in Radical Red, some being made as late as Version 4.0 (such as Raichu becoming Electric/Normal). As such, there's a good chance that even more type retcons will happen in future versions. Here are some ideas:- Hero Form Palafin: Water/Fighting instead of pure Water.
- Haxorus: Dragon/Steel instead of pure Dragon.
- Garganacl: Rock/Normal instead of pure Rock.
- Melmetal: Steel/Fighting instead of pure Steel.
- Rillaboom: Grass/Normal instead of pure Grass.
- Cinderace: Fire/Fighting instead of pure Fire.
- Inteleon: Water/Psychic instead of pure Water.
