Resources: chess.com, 365chess.com (B20)
1.e4 c5
Sicilian Defense, one of the oldest, an opening that goes for aggressive center play, dating back to being mentioned in the 1500s, has 3 main variations:
Closed (3. Nc3),
Open (3. Nf3) and
Alapin (3. c3)
For the Open variation, there are 3 standard lines:
* 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4
or
1.e4 c5 2. Nf3 e6 (French variation)
1.e4 c5 2.Nf3 Nc6 3.d4 (B32 line)
*The 4.Nxd4 line can be followed by .. Nf6 5. Nc3 leading into two new variations:
Najdorf variation (5. .. a6) and
Dragon variation (5. .. g6).
For ..g6 move, it's worth looking into the Accelerated Fianchetto/Dragon variation, as it can be one very long textbook opening set.