Gambit against 1.e4?

I believe the Portuguese is 3...Bg4 vs. 3...e6 for the Icelandic Gambit, right?

3.c4 e6 is the Icelandic Gambit, while the Portuguese arises after 3.d4 Bg4.  At the GM level, 3.d4 is much more common than 3.c4.

If you are planning to play the Portuguese or the Icelandic, White might be a spoil sport (me) and after 1.e4 d5 2.ed Nf6, play 3.Bb5+ Bd7 4.Be2 Nxd5 5.d4, when the play resemble the 2...Nf6 Scandinavian main line (1.e4 d5 2.ed Nf6 3.d4 Nxd5)

Though engine refuted (+.9 or something), the Rousseau gambit has been great to me from 600-950.  It's like a reverse vienna off of the Italian game.  Black is better if the pawn is taken, and it is extremely easy to neutralize. 4. d3 is a the best move for white, not taking.

The Two Knights Defence:
1 e4 e5 2 Nf3 Nc6 3 Bc4 Nf6 4 Ng5 wins a pawn by force for white
The Marshall Attack:
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

Yes, the OP who asked the question 12 years ago will certainly be glad to read these great suggestions.

Latvian Gambit is a tricky but fun gambit to use.