Monopoly: I guess you are thinking about sleeving the incident cards, not the money (hopefully). If I take the cost of Monop. into account, I´d recommend not to sleeve it at all.
C) Dixit (do they even have sleeves this big?)
Yes, they exist.
Always know your "cost of sleeving : price of the game" ratio! If my calculations end up with results like I had to pay as much as the game costs to sleeve it, I mostly don´t sleeve it.
Generations of kids played UNO without any sleeves.
Take my opinion FWIW, if you want to sleeve them all, it is definitely possible! If you want to support your local business, why not enter their stores and ask them "What sleeves do you recommend for the following games: ... "??