A friend and I had a ball last weekend playing tournaments of Family Feuds, Wheel of Fortune, and Monopoly on the SNES. The latter made me wish there was a romhack that implemented the 2005 Super Add-ons For Monopoly by Radgames.
What that expansion does is add an inner board on top of the game board, and two forks on the road to enter/leave the inner board. Basically, whenever you reach one of these forks, if you rolled an even number, you switch track and hop onto the inner/outer board, and if you rolled an odd number, you don't switch track and keep going forward as usual. Because the forks on the road allows players a chance to dodge certain properties, you can't just build that death trap with the orange and red properties, you must invest on both boards.
I couldn't find a hi-res picture of the original board itself, but here is a picture from a modified DIY version:https://www.mafiascum.net/images/img-tags/oSm3EA2OisKbspwFe6HF.png
If you walk in front of the Transit Station, you may (or may not) switch track depending on the odd/even results of your roll.
This DIY version use the same mechanics as the Super Add-ons, but removed a lottery square (that injected ludicrous amount of money into the game with no investment required) in favor of the Stock Exchange square (another Monopoly expansion that can adds (or remove) money into the game but requires the players to purchase stocks in order to earn dividends later).
As you can see, the inner board contains twelve new properties split into four lots, and two additional public utilities (If you own three public utilities, the rent is 20 times the value of the dies, and 40 times the value of the dies if you own all four utilities). The additional properties makes games with 6 to 8 players much more enjoyable, since every players has at least a chance to build something before all the properties get sold.
In addition to that, it also has a Chance and a Community Chest squares (with additional cards to suit this new board); a Go kind of square (that gives 250$ if you pass it or 300$ if you land on it); a Tax Refund square (that functions like the Free Parking cash house rule, but the refund is only 50%, not the entirety of the tax money pool); and a bunch of others squares too long to explain.
You can find additional info about the Super Add-ons on the Monopoly wikia:https://monopoly.fandom.com/wiki/Super_Add-ons
Heck, additional rules to speed up the game could also be implemented, like the possibility to build depots on the train stations to double the rent, presents in some special editions of Monopoly.