Looking for a good and non main line variation against the Sicilian I am looking for a nice variation against the Sicilian, which is a little bit aggressive but mainly not part of the main line like Nf3, d4, b4 or c3 after e4 c5.

The thing is, I don't want to learn 20 variations, which I have to do if I play the main openings.

Which one do you like to play / recommend me?
It's a bit difficult to recommend an aggressive line that doesn't fall into the variations that you listed. However, I believe there is an option that may suit your tastes. The Rossolimo with 2. Nc3 is venomous choice that's played at the highest levels and contains many lines that are quite dangerous for black. Here's one of the opening traps:

[FEN ""]

1. e4 c5 2. Nc3 Nc6 3. Bb5 Nd4 4. Bc4 e6 5. Nge2 Nf6 6. d3 a6 7. O-O d5 8. exd5 exd5 9. Nxd5 Nxd5 10. Nxd4 cxd4 11. Qh5 Be6 12. Re1


I recommend that you look more into the opening yourself and discover some more interesting lines.