Tricks and Glitches

Infinite Money Glitch (Old versions only)

If a worker is in range to place a structure, but it cannot path to place that structure, it will place it anyway but refund the resources. These videos: https://www.youtube.com/watch?v=rmrgi0N7HX0, https://youtu.be/kWsgPMd3Zmg

No Item Cooldown Glitch (Old versions only)

In old versions of WC3, if you transfer items between heroes they lose their cooldown, and if you target an item somewhere, and then move another item into the slot of the item you are targeting with, you will use the item in the slot that you originally targetted . I haven't tested the following, but according to patch notes it also works if you just drop and pick up or sell and buy items.

Displacement Glitches

One thing to note: At least in new versions of Wc3 (idk about old ones), displacement glitches do not allow you to go up or down cliffs (not even if there is a ramp connecting them).

Displacement Glitches occur when the collision radii of two units are on top of each other. The unit that next has a pathing update (caused by the stop command, the move command, or just continuing to move), it will find the closest free place to put it within a certain radius and put it there.

Using a worker (or hero with tiny building) to build a building on top of itself will cause the worker or hero to be displaced.

Summoning units causes displacement.

Mirror Image causes displacement

Unit creation causes displacement (through triggers or normal spawn). Note that in normal spawn, the unit will appear at whichever corner of the building is closest to the rally point. Unit creation displacement from building is centred on the building and not the spawn point.

In old versions of Warcraft 3, workers turn off pathing when instructed to gather lumber. This allows for displacement glitches. Ordering the worker to do something else will displace the worker, and alternatively when the worker reaches a tree it turns pathing on, meaning that the next time a unit underneath the worker has a pathing update, it will be displaced. In new versions, worker pathing is a very tricky thing indeed.

Healing ward glitch

Healing wards can be sort of "displaced" but not really displaced. This can grant vision. It's sort of weird how it works, I haven't looked into it. Watch this video: https://www.youtube.com/watch?v=jrn5M-yytdk

Illidan Silence glitch

If Illidan is Silenced while channelling to close a dimensional gate (or indeed probably anyone is silenced while channeling any spell), he will stop channelling. Watch this video: https://www.youtube.com/watch?v=1RRRDMOHDy4

Death at end of channel glitches (Old versions only)

Death of mountain king at end of avatar will result in an invincible, uncontrollable mountain king (you need to be near enemies for him to get up and start attacking things)

Death by faerie dragon ability for a channel spell will cause the spell to occur forever. Not very useful seeing as the AI doesn't use faerie dragons, but maybe it could be triggered somehow else?

Town portal to moving tree of life

In new versions you will go invincible for a time but (assuming you placed the tp scroll at the edge of it's radius), you will get your scroll back. Doesn't work in old versions, you just lose your scroll.

If a hero dies, they will be respawned in most cinematics

Extracting maps with MPQ editor

You can extract the maps with this MPQ editor: http://www.hiveworkshop.com/forums/tools-560/ladiks-mpq-editor-32bit-249562/

Less Useful Stuff

Infinite Ankhs

Also, in the last human mission ROC, there is a trigger that periodically gives Mal'ganis ankhs of reincarnation, to make him 'invincible'. If you kill him repeatedly rapidly enough, he will die anyway, and an ankh will repeatedly and periodically spawn on the ground where he died. Works in the current patch (1.27a). Pretty useless but cool anyway.

Quicksave

Also, if you press F6, you can quicksave. I believe this can be used in old game versions to save after a mission has ended (although I haven't tried that yet), judging by the patch notes. I was trying to really quickly press the hotkey sequence to do it, but it would be much easier just by pressing F6. You can also do this to ever so slowly ignore a cutscene, because you can always save just before the cutscene starts and the next time the cutscene will start a little bit later. If you press Alt-f4, you can pause during a cutscene, which stops the camera from moving and stops fadein/fadeout (It asks whether you want to quit). None of this is useful though :(.