Monopoly sucks. But it's also sort of endearing. It's like a crazy family member that should probably have been disowned by now, but there's all the memories and an underlying sweetness and family is family and that's just not what we do in this household, okay? Anyway, despite having introduced the family to a million better board games, the nostalgia of Monopoly finds a way to ensnare people back to it. There are many fundamental problems with the game that I'm not attempting to solve here. What I am trying to do is inject some variety and decision-making into the game.

For now, I'm calling it Monopoly: Moral Ambiguity. All of the Chance and Community Chest cards are being replaced by Scheme cards. Whenever you land on a Chance or Community Chest spot, you discard all other Scheme cards you possess and place the new Scheme card in front of you. These Scheme cards alter the rules of the game for you and remain in place until you draw a new Scheme card.

What do these Scheme cards exactly do? That's where I need your help! I've figured out some ideas (and playtested them, which is how I cam to the conclusion that everyone should get their own abilities rather than there be global effects... though maybe a mix of both could work), but I'm looking for much, much more! Here are some examples:

Backtrack: Whenever you roll dice, you may move that roll in the opposite direction. Advancing past GO only awards you money when traveling around the whole board in the regular direction.
Traffic Disregard: You may roll 1, 2, or 3 dice. Doubles only award extra turns when rolling exactly 2 dice.
Panic Stop: Whenever you land on a space occupied by an opponent, collect $50 from that opponent.
Overcharge: All properties you own charge opponents double all values.
Editor's Will: You may reroll up to one die once per roll.
Marketplace Overload: As each of your turns start, you may choose an unowned property and put it up for auction.
Insider Trading: Whenever you complete a trade, collect $100.
Swoop and Squat: Whenever another player lands on the space you occupy, that player goes directly to jail.

In general, cards that reward you with money are really easy to come up with, so I don't need help there. (Unless they're like Insider Trading, helping to push part of the game.) Also, injecting more money into the game is generally what leads to Monopoly lasting forever and feeling miserable.

Post your ideas!

The Editor's Will and Swoop and Squat cards make me think you should have some sort of last will and police mechanics.

The former is relatively easy, since you only have to devise a way for players to leave instructions for divvying up their holdings. Not entirely sure how you'd go about it, though. My main point is so that players who are eliminated have a way to make their deaths meaningful.

For the police thing, you could have a sort of debt mechanic where players may choose not to pay fees, but then have another piece on the board that is "the policeman" who can move in either direction. Maybe it would be best to have the policeman operate on cards, like "The Policeman patrols the railroads for the next 3 turns" or "The Police have received reports in the Boardwalk district" (at which point the Policeman token would move toward the Boardwalk each turn and players would have to avoid him). Any player in debt (having not paid fees) is sent to jail until they can pay off the debt with interest?

A last will sounds awful. Games with political elements already have kingmaker problems, and this just seems like a way to choose a winner. These cards are suppose to either help you win or help others lose.

The police idea feels like an over-complicated version of Swoop and Squat. One of the issues is that players actually land on Chance and Community Chests quite often. You can't expect to have any one card for longer than a few trips around the board. Anything that becomes to intricate ends up not mattering enough to be fun.

Purchasing the Fourth Wall: You may spend real money.

I barely know the rules to Monopoly, which I guess I should be thankful for. I think the Norwegian version makes a player win if they reach a certain sum instead, which makes more sense. Anyway, I would make the player choose between which Scheme to keep, and then have a handful of scheme cards that give immediate benefits when you draw it, for some short-term versus long-term tension. Means you need to balance the schemes better though, and have them be more contextually situational.

That adds a rather natural decision matrix, but it also makes the development process harder and camping on one super beneficial card easier. Right now, the experience of getting new abilities excites me more. There's still the possibility that gathering multiple abilities (ala King of Tokyo) is feasible.

Is taking an extra turn after rolling doubles even part of the core rules? Honestly, with all the alterations people make, it's hard to keep track.
Taking out hotels will speed up the game since it nobody will put houses back into the available pool.
Setting the Monopoly board on fire also does wonders for the excitement level.
Overcharge seems overpowered. If you can get that ability and manage not to swap it out for another, you are likely going to win.

I recently discovered Monopoly Empire. If you are not familiar, check it out. It is the only version of Monopoly that I have ever enjoyed, and it shares some aspects with your idea. Mainly the replacement of community chest with a different kind of card. Also, they created a win condition that isn't "make everyone else ragequit".

Stock Market Fiend: for each even number you roll on the dice, gain that amount of money times 10 (a 2 is $20 in your pocket, a 6 is $60), for each odd number rolled, lose that amount of money times 10. If you roll double 1s, discard this scheme card after paying up.

Alternatively, times the values by 100 if you're a gambling man.

That would work out to not really doing much.