What are the most aggressive openings ever?

Fried Liver Attack is very aggressive.

I think that as white, there is no question, that hands down, #1 is the King's Gambit!!! (My fav) Otherwise the dutch gambit is quite agressive as well (and exciting). Then there's the nutty ones like the Halloween Gambit - hard to get much more agressive than that! A simple look at Morphy's openings (renowned for their agressive and fast nature) will reveal a gold mine of these!

As black, I would lean towards the center counter game (1.e4 d5) as it often brings out the queen early and makes more early tension and pressure in the game. Almost as agressive if not more at times, is the relatively obscure 'Bird's defence to the Ruy Lopez' (1.e4 e5 2. Nf3 Nc6 3. Bb5 Nd4!?) which has some sharp and interesting lines, including the flight of white's light bishop...

Just off the top of my head...

What about lativian gambit and danish gambit

I forgot about the bird's opening!!!

sicilian nadjorf and sicilian dragon

Trompowsky attack.

Fried Liver attack.

 Bird's opening isn't aggressive. From my experience against it, it's one of the least aggressive and easiest for black to equalize against.

Henry Edward Bird thought 1.f4 was the best move for white.

And bird was wrong.

Why.

fried liver attack

I used to play the Bird a lot. Every game used to be the Bird. And from what I gathered, it was not too aggressive. The aforementioned King's Gambit is quite aggressive, along with, in my opinion, the Ruy Lopez. The Grob, 1. g4, I can't help but think is aggressive in nature, albeit it gives Black opportunities for a counterattack due to the openness of White's king (that's why you castle Queenside when you can in the Grob!).

Fried Liver Attack.

Followed by the Lolli Attack.

what is the lolli attack

http://www.rci.rutgers.edu/~goeller/urusov/perreux/lolli_attack.html

The Lolli attack reccomends 6. d4 instead of the usual line, 6. Nxf7.

Any "attack" that relies on your opponent making a mistake isn't worth much discussion.  By that criteria, Fool's Mate is the most aggressive opening that exists.

As far as openings that consider best-response... hmm, there are a lot of crazy candidates.  There's nothing saying that YOUR moves have to be good, so some of those early Nxf7 variations have to qualify, many of those are well beyond sound.  Come to think of it, there are a lot of variations in the King's Gambit of questionable soundness.

If you want something relatively *sound* as well -- or at least, "unrefuted" -- there are still a lot of choices.  Najdorf Poison Pawn, Danish Gambit, Blackmar-Diemer Gambit, Latvian Gambit are all legitimate candidates.  But I'd have to vote for the Traxler Counterattack (1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 Bc5!?).  That thing is crazy.

2 knights Traxler is pretty bonkers.

King's indian Attack followed by fried liver attack

Traxler Variation in the Two Knights Defence, Belgrade Gambit in the Four Knights Game, From Gambit in Bird's Opening, Frankenstein-Dracula variation in the Vienna Game, Dragon Sicilian, and the Double Muzio Gambit in the King's Gambit to name a few.