I wasn't aware that they were missing, or that I ever had any to start with?

You mentioned Monkey Island, so I though you knew about the "Insert disk..." joke.
https://i.ytimg.com/vi/VYP8t7-Dbrk/maxresdefault.jpg

Oh yes, that rings a bell :) Weirdly that kind of fourth wall breaking doesn't bother me. Perhaps it's only when the characters say or do something to suggest that they know they are in a game.

I found another one I really like. It's the Joker's ending in MK11. He breaks the fourth wall in the most literal sense.

"Or maybe I'll just break your TV"

SaGa 1 (Final Fantasy Legend 1) major spoilers ahead (also some for SaGa Frontier):

In SaGa 1, there is some evidence that you are actually playing a game. Specifically:
* One side floor has a library where the books have the names of adventurers and the floor they reached, much like a high score table. (Note that, in the English version, the text here has been changed completely, losing this effect.)
* At the end, the Creator (who was apparently God in the JP version) reveals that the world and path to paradise was a game that he created, and you have to fight him. (It's a moderately challenging fight, as final bosses go, unless you happen to have a saw handy.)

SaGa Frontier: Blue's ending is a bit strange, as the game will appear to freeze as soon as you inflict the final blow on the final boss. (It is one of the strangest endings I've ever seen in a video game.)

I could also mention that many games do fourth wall breaks in order to explain the mechanics, or to suggest that you should save the game before continuing. It can also be used to tell you the controls; I believe Dragon Quest 5 (SFC version) tells you to press either the red or blue button to perform actions without opening the menu. (On the SFC controller, A is red and X is blue; unfortunately, the SNES controller is rather boring by comparison.)

Bernd das Brot und die Unmöglichen

An Adventure just relased in german language afaik.
In fact that game is already starting with breaking the 4. wall and doing it again all the time.

You will play this bread www.youtube.com/watch?v=Y19soCjLO7Y dressed up as some kind of Batman, trying to find out what happend to the bronze statue of the card playing Yakk, that has a cold.

I don't think I have to say more...

My favourites would be Conker's Bad Fur Day when he literally speaks to you as if he was right there throughout the game.

Deadpool also does this sometimes as well, my most favourite would be when the voice in his head constantly fights with him about sticking to the script of the game xD I absolutely loved it!

Tolkien often broke the fourth wall, talking directly to the reader at times in his famous Lord of the Rings trilogy.

(I believe this aspect didn't make it into the movies, however.)

When I remember correctly Tolkin reffers himself as the translator of the story from original text and this way he is a narator too.
We don't got that roll in the movies.

I wish it were only "sometimes". It went from occasional and somewhat funny to frequently overused and less amusing as Deadpoolmania saturated everything.

True, was still fun tho.

Final Fantasy 2 (GBA and possibly later versions) has an interesting one:

If you hack the Killer Bow into your inventory and check the description, it says something like "if you're seeing this, you've either found a bug or are a l33t haxx0r". (Note that the Killer Bow isn't actually obtainable in the game, so you won't see this message unless you hack it into your inventory, or if there is some glitch I don't know about.)

(This particular weapon existed all the way back in the Famicom version but was never obtainable legitimately.)