Remarkable family of 15+ normal central gambits including Blackmar-Diemer, Danish and Smith-Morra

We have distinguished 12 families of normal central opening hierarchies:

• 2Cc Symmetrical English
• 2Cd Anglo-Scandinavian
• 2Ce King's English
• 2Dc Old Benoni
• 2Dd Queen's Pawn
• 2De Englund
• 2Ec Sicilian
• 2Ed Scandinavian
• 2Ee King's Pawn

https://www.chess.com/forum/view/chess-openings/classification-and-taxonomy-hierarchy-of-normal-central-openings

There is also a natural family of associated gambits.

• 2Cc Liedmann gambit

• 2Cd Anglo-Scandinavian and Loehn gambits

• 2Ce King's English gambit

• 2Dc Cormorant and Old Benoni gambits

• 2Dd Accepted Queen's and Blackmar-Diemer gambits

• 2De Englund Complex: Hartlaub-Charlick and Soller gambits

• 2Ec Smith-Morra

• 2Ed Blackburne-Kloosterboer and Scandinavian gambits

• 2Ee Danish

If we include intermediate knight moves, it will give a lot of additional "natural" gambits like Goering gambit:

Let's start to analyze a bit these gambits. 

2Cc Symmetrical English -> Liedmann gambit

In this position

the best move for white is, of course, 3. Qxd4. Now, if white wanna really play gambit, the best option might be 3. Nf3. It will give something like that (ev=-0.8):

The Liedmann gambit itself has a similar evaluation.