Ranking Gambits for Black

#21 then you either face d4 very rarely or your opponents have no clue, White is better in every line

I don't think this gambit has a name and white has the option not to go into it, but in this gambit black is objectively (and practically) better despite being down a pawn. 
1. e4 d5
2. exd5 Nf6
3. c4 c6
4. dxc6 Nxc6
White should play 3. d4 or 3.Bb5 or 3.Nf3 or even 3.Nc3 all of these moves are better than 3.c4, but inexperienced players think that making this opening a gambit by playing 3.c4 has to be objectively good for white and dubious/unsound for black, which is the exact opposite of the truth.

not going to rank the countergambits, but here's their stats between 1600-2000. to ME, a truly "sound" gambit beats one's opponents more than 50% of the time, like king's gambit, blackmar diemer and french wing gambit etc.

i was very disappointed to see the albin performing equally. i wanted to study it, but benko performs so much stronger it must have more teeth. at the amateur level, gambits are winning and no grandmaster quotes will ever change that. statitistics bear it out.

i was planning on doing this for the big gambits list at wikipedia. it would take a long time though as there's so many.

i would put latvian gambit at the bottom of this list regardless of stats unless one considers inviting white to keep developing pieces that chase one's queen the first dozen moves a proper gambit! there's no initiative in it at all. i wanted to play it as a reversed king's gambit too. i took a few mini scalps at first, but once everyone got over their surprise, i started getting waxed quickly more often than not

1. Two Knights Defense: 50:46@5.2m +0.2

    1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 

2. Marshall Attack  41:54@108K +0.6

    1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.O-O Be7 6.Re1 b5 7.Bb3 O-O 8.c3 d5

3. Benko Gambit: 44:52@541k +0.8

    1. d4 Nf6 2. c4 c5 3. d5 b5

4. Von-Hennig Schara Gambit: 47:48@34k +0.6

    1. d4 d5 2. c4 e6 3. Nc3 c5 4. cxd5 cxd4!?

5. Jaenisch Gambit (aka Schliemann Defence) 44:52@214k +0.6

    1. e4 e5 2. Nf3 Nc6 3. Bb5 f5

6. Rubinstein Countergambit (4 Knights): 47:49@81k = 

    1. e4 e5 2. Nf3 Nc6 3. Nc3 Nf6 4. Bb5 Nd4

7. Budapest Gambit: 47:48@1.2m +0.7

    1. d4 Nf6 2. c4 e5

8. Blumenfeld Gambit: 47:49@11k +0.6

    1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nf3 b5

    1. d4 Nf6 2. c4 e6 3. Nf3 c5 4. d5 b5

9. Icelandic Gambit: 44:52@347k +0.7

    1. e4 d5 2. exd5 Nf6 3. c4 e6

10. From's (Schlecter) Gambit: 51:46@55k +0.9 

    1.f4 e5 2.fxe5 Nc6

11. Bellon Gambit: 50:47@1,117 +0.7

    1. c4 e5 2. Nc3 Nf6 3. Nf3 e4 4. Ng5 b5

12. Albin Countergambit: 49:47@943k +0.9

    1. d4 d5 2. c4 e5

13. Elephant Gambit: 47:49@1.2m +1.2

    1. e4 e5 2. Nf3 d5!?

14. Englund Gambit: 49:47@6m +1.7

    1.d4 e5!?

15. Colorado Gambit: 46:50@171k +1.4

    1. e4 Nc6 2. Nf3 f5

16. Ross Gambit: 53:44@958k +1.6

    1. Nf3 e5

17. Latvian Gambit: 48:48@665k +1.7

    1. e4 e5 2. Nf3 f5?!

18. Herrstrom Gambit: roughly even stats… too rare to make list

    1.Nf3 g5

19. Stafford Gambit (aka Russian Game): 50:46@6.5m +0.5

    1. e4 e5 2. Nf3 Nf6

20. Busch-Gass Gambit: 53:44@1.2m +2.2

    1.e4 e5 2.Nf3 Bc5

21. Falkbeer Counter Gambit: 47:50@861k -0.3

    1.e4 e5 2.f4 d5

22. Scandinavian Gambit (everyone transposes to Pavnov Transfer now): 43:53@381k =

    1.e4 d5 2.exd5 Nf6 3.c4 c6 

23: Traxler Counter Gambit: 47:51 at 267k +1.4

    1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 Bc5

what's the rest of your repertoire? I've been wanting to drop the stonewall for the albin, but don't know any other lines to supplement it.

you know, technically, the scandinavian is a gambit, especially if one plays the marshall variation and doesn't take the pawn with the queen

1.e4 d5 2.exd5 Nf6 - pawn has been gambited and black is worried more about development. it might not be considered a gambit, but it is. 47:49 at 4.4m +0.7

Brombacher Countergambit: 46:49 at 6k -0.4

1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 c5

Calabrese Countergambit: 49:49 at 94k +1

1.e4 e5 2.Bc4 f5

Rubinstein Countergambit : 50:44 at 1,665 +0.6

1.e4 c5 2.Nf3 Nf6 3.e5 Nd5 4.Nc3 e6 5.Nxd5 exd5 6.d4 Nc6

Gary (Kasparov) Gambit: 48:43 at 112 +0.6

1.e4 c5 2.Nf3 e6 3.d4 cxd4 4.Nxd4 Nc6 5.Nb5 d6 6.c4 Nf6 7.N1c3 a6 8.Na3 d5  

After

22. Scandinavian Gambit (everyone transposes to Pavnov Transfer now): 43:53@381k =

    1.e4 d5 2.exd5 Nf6 3.c4 c6 

I have found people play 3...e6 and go to the Icelandic Gambit

that's what i do now. i resisted it hard before i quit a decade ago, but got sick of seeing nothing but pavnovs these days and switched. no one knew pavnov circa 2005! in fact, i had to teach an actual pavnov player the scandinavian move order.

i'm liking the icelandic gambit a bit more now too as i play it on the white side as the monte carlo french. 

I play King's Gambit and open Sicilian as white, Sicilian as black. I also have the Semislav and Catalan for black prepared against anti-Albin d4 players.

mosquito gambit

udnerestimating latvian gambit imo. also what about the fajorowitz?

E

Does anyone have a hard time dealing with e4? I've created an opening for black against e4 and if you really want to learn the Stafford Gambit for black although there is no named Stafford Declined but I named it if the opponent try to declined the Stafford gambit. Stafford Gambit and Stafford Declined is the best choice to beat your opponent quickly against e4. It's carefully analyze by the strongest computer engine, Stockfish 15. You can beat anyone to win easily with black and increase your rating quickly. For those who wants to get the access for the save pgn, comment your Gmail account below and it's time to beat your opponent.

Cut the crap. If this were true, all GMs would play the Stafford.

the latvian gambit is pure garbage! i tried playing it as a reversed king's gambit. i had some quick wins, for a minute, because of surprise value, but it wasn't long before i started losing almost every game. i don't even know why it's called a gambit. the idea of a gambit is rapid development, not having your queen run screaming from piece after piece while your opponent develops. i'm a gambiteer, but the latvian can eff off as far as i'm concerned.

in looking at stats, i see that black can steer the game towards winning, but i just remember getting waxed regularly playing it and giving up when i borrowed a book and saw lines where black only moves his queen for up to a dozen moves. i like my queen, but only bring her out with minor piece support if i have a choice. defending with her and/or running for cover is hideous.

what line do you dislike, I'm pretty sure blacks queen is not attacked by many pieces in most lines

what about vienna

Rousseau Gambit

1. e4 e5 2. Nf3 Nc6 3. Bc4 f5

By the way, haven't studied it but my impression was that #6 "Rubinstein Countergambit" (Nd4 after white's Bb5 for black in 4 knights) was best play & completely equalizes. So I'd put it higher (if my recollection is correct)

In real life, my rating is about 1500. I play the Icelandic (within the Scandinavian) whenever I get the chance. Also the Budapest. I have had great success with the Icelandic, including in OTB play against opponents 100-200 points higher than me. Not so with the Budapest though. 
It would be interesting to see a list of gambits and the corresponding rating at which they stop being effective.