Dota 2 has always been a game of innovation. There have been great e-sports athletes who have always found them out and exploited them to great ends.
Some instances have been etched in the memories of Dota 2 fans forever, like the Fountain Hook, while some of them are still lesser known to the general population of the game.
The most useful exploits in Dota 2 that actually work
#1 Ward gold by transferring observer ward
This is a trick that can earn the ally carry or mid-laner an early bottle, or some extra gold to the ally carry for the farming item, etc.
If the core player gives his observer ward, which is free to the support, and if the support already has a sentry ward, once they are in the inventory, both the wards will be displayed to belong to the one who gives the ward.
More importantly, if the support dewards with the sentry ward he bought, the deward gold will go to the carry.
#2 The tier 1 tower's night vision and range
Another lesser known fact of Dota 2 is that the tier 1 towers of any lane have lesser night vision than their range.
Since the games of Dota 2 now start off at night time, one can stand inside of the tower range, around 2-3 units inside of it, and not get hit by the towers.
If the said hero is being hit by the towers, then it is guaranteed that there is a ward placed, and its an easy deward for the lane.
#3 Messing with the opponent mid-laner
This looks like a silly strategy, but it works. The roamer support pokes the mid-laner for small bursts of damage.
This does two things. It takes away some of the regen from the laner, and it messes up the block. This also helps tip the lane equilibrium in favor of the ally mid-laner.
#4 Tricksters' Cloak
The Nullifier is a very powerful late game item that dispels the target and applies a debuff for 5 seconds, continuously dispelling the target. Anytime the target is attacked, it will be slowed by 80% for 0.5 seconds.
This even dispels the Aeon Disk, which does not work, thus making the item a waste of gold. The answer to this lies in the neutral item, The Tricksters' Cloak.
That Tier 4 Neutral Item stays on even after the Nullifier is applied, and is a broken item for squishy heroes against nullifier carriers late in the game.
#5 Locking the Aghanim's Blessing recipe
This was a trick that Nico "Gunnar" Lopez brought to the fore. Late in the game, if a hero has slot problems, then sometimes they consume their Aghanim's Scepter as the blessing. Gunnar suggested keeping the recipe in the backpack locked, and using it only when absolutely needed.
This is because the Scepter provides some key stats that could allow the hero to escape a teamfight with 10 or 15% HP remaining.