I thought it would be fun if people shared their dreams and ideas of hypothetical extensions or changes to video games.
You can be as specific as in my example below or as general as just sharing a game idea you’ve wanted to build if you had unlimited skills, resources and time (doesn’t even have to be an extension of an existing game, the topic probably won’t have overlap anyway).
I’ve made some graphics of extended areas to my favourite pokémon generation (gen II). I have a vision that’s pretty specific: to remake a more extensive Kanto region, and also include the ability to catch every 251 pokémon from the first two generations in the same game. I always thought the deviance from the original games should be minimal to none, because the original designers knew what they were doing. The problems are generally overblown and overcorrected by contemporary ROM hackers.
Here’s the original Viridian Forest in RBY (Red/Blue/Yellow) compared to GSC (Gold/Silver/Crystal):

Most of the work I’m talking about would essentially be to implement almost exact copies of the more extended areas from RBY into GSC with the second generation’s spritesheets.
The original Kanto Route 25 in RBY:

The original Kanto Route 25 in GSC:

My remade Kanto Route 25 (right-click -> open in new tab -> remove from “&w=” and everything afterwards in the URL to see full-size):

Sometimes I’ve added trainers and sometimes I haven’t. This is not fully incomplete. ^^
My remake of Sea Cottage (Bill’s House):

Below is my completely new area north of Route 25, which I have the placeholder name “Bill’s Garden” for, reachable by going through Bill’s House. The transparent sprite would be, like, a Chansey you could corner and fight after you’ve chased it similar to Farfetch’d in Ilex Forest, so it would only be there once I guess. I also thought Mew could spawn on the island to the north-east after every other pokémon is caught, and then it could be chased around the entire map in a fashion similar to Suicune in Crystal.

The original Kanto Route 27:

My remade Kanto Route 27 below. I thought Lance could look down from a cliff as you passed the first time as foreshadowing. The transparent boulder in the north-west could be removed after some trigger in order to give access to the extended area, I guess after defeating the pokémon league. I should’ve added some swimmers to the south-east and done minor modifications.

My remade Pewter City:

My remade Seaform Islands B4F where Articuno is found (using the Crystal spritesheet from Ice Path in Johto):

My remade Silph Co 1F:

My remade Silph Co 1F, alternate version:

My remade Viridian Gym, although the spritesheet for this was cooler in the original GSC Viridian Gym, so one should use that instead of mimicking RYB like I’ve done here (I mainly wanted to add trainers):

And finally a cooler version of Mt. Silver, but also giving easier access for those who just want to fight Red and not explore the whole cave:

Some day, I might make a ROM hack for GSC, although I’ll probably procrastinate this indefinitely. I made these images more than a decade ago. If anyone more productive than me reads this in the future and wants to use my designs in a real mod, you are more than welcome to do so.
Again, you don’t need to have any art or specifics like this to participate in the discussion. Please just share your dreams and ideas for your favourite games with your own words, I would love to read them. =)