Infinite Coin Glitches
Infinite Coin Glitches are a category of glitches that allow Mario to collect infinite coins.
Main article: Cloning
By grabbing an object as it unloads, Mario can hold a fake object. A coin may load into the fake object's slot and Mario can then hold the coin. If the coin comes from a coin spawner, Mario can load the coin again by leaving and re-entering the coin spawner's radius, which would theoretically lead to infinite coins; however, each clone takes up an object slot, so unless a method of resetting the level such as a loading zone or sub-area is available, only a finite number of coins can be cloned before the object limit is reached and the game crashes.
Moneybag duplication is a glitch which causes a Moneybag to duplicate itself into two Moneybags. By waking it up on the same frame it goes to sleep, you can cause it to create an awake one as well as an asleep one. Since these are technically separate objects, there are now two moneybags. Moneybag duplication can be used to get infinite coins in Snowman's Land.
- In the ABZ Challenge, extra moneybags are useful for some stars in Snowman's Land because you can bounce on them to get extra height.
- Rapid Moneybag Duplication 
This is a trick to duplicate the Moneybag rapidly. This was found by Tyler Kehne. The Moneybag will duplicate if Mario enters within 800 units of its home on the same frame that the Moneybag enters within 100 units of its home. So by oscillating in and out of this 800 unit radius, we can duplicate a new Moneybag every 2 frames. This technique should lead to faster SL 100 coin star times.
One caveat though is that there is a 1/50 chance that the Moneybag's home will instantly translate 200 units to the side when awakening it, meaning that there's a 1/50 chance that the rapid duplication could come to an abrupt end. When going for a WR time, we'd need to get a better RNG sequence so that we could continue duplicating without this issue.
Breaking-Disappearing Cork Box
Main article: Breaking-Disappearing Cork Box Glitch
The breaking-disappearing cork box glitch is caused by breaking a cork box right when it disappears. This way it will respawn, but will also give three coins from breaking. The easiest way to do the glitch is to place the cork box on top of an object that becomes intangible when Mario moves away, and then returning to make the object tangible right when the box disappears.
This method of infinite coins does not take up object slots, and so it can be used to create more coins than cloning would. Infinite coins via cloning would eventually crash the game.
It is also possible to do this glitch while also grabbing the cork box fake by having the box break by touching the wall of a moving object.
Main article: Timestop
This method is only possible on the Japanese version of the game. It requires the player to be able to move around while most of the level is frozen because of a textbox. This is achievable in multiple ways, such as jumping at the same time as a proximity-based textbox is activated. In this state, coins can be collected but do not unload until time is resumed.
The player can exploit this by stopping time, collecting a coin, and entering a warp zone. This means that the coin is collected but doesn't unload, so you can return to the area with the coin and repeat.
Main article: Ride Cancelling
When Mario gets off of a shell, the game sends a "signal" that the shell uses to decide that it should unload. The "getting off a shell" signal overrides other signals, so if the player gets off a shell at the same time as collecting a coin, but the stop riding signal will prevent the coin from actually unloading.
This process can be repeated by using a cloned shell, which allows for the shell to be reused multiple times.