One well known very good combo is the Caro-Kann + the Slav:
- The main objective of both of these openings is to develop the light-squared Bishop to f5 before it gets locked inside the Pawn chain.
- They tend to lead to roughly similar Pawn structures.
- On average they both tend to lead to positional, quiet and strategic games.
- And most importantly, if you choose both of these openings, against 1. c4 you can play 1...c6 which can transpose into either a Slav (2. d4) or a Caro-Kann Panov/Pseudo-Panov (2. e4).
I would like to know what are all the other possible combinations of openings which work well together.
Enumerate as many combos as you can. But I am only interested in combos where both openings are sound.
And if possible also explain why exactly the openings work well together.