Posters may wish to opine on what they think are some underrated chess openings. In my spare time now and then I take a cursory look at what might qualify, at least as (somewhat) interesting offbeat openings. In the past I looked at books for assistance coming up with such material, but nowadays databases can also be helpful. Chess Assistant 16 (CA16) is a database program that rates a huge number of move sequences, looking at the terminal position of many with an engine for an unknown amount of time (besides providing human evaluation symbols at times). Since all of what I have in mind for White is considered fully playable by most books and/or databases (one luxury of moving first is a rich selection of palatable offbeat choices), I'll show what are CA16's numerical evaluations for all of poor Black's openings, i.e. those offbeat (and suspect) ones that I found to be of interest recently. Note I included options vs. White's fully respected 1st flank moves (1.c4/1.Nf3/1.g3) - someone once noted they had not much offbeat to play vs. those, so why do so vs. 1.e4 and 1.d4(?):
Black:
vs. 1.e4:
1...d6 2.d4 Nf6 3.Nc3 Nbd7 (intending ...e5, Philidor Defence-like): 0.33;
1...e5 2.Nf3 Nc6 3.Bb5 f5 (Ruy Lopez Schliemann Defence [or Jaenisch gambit]): 0.44;
1...c5 2.Nf3 a6 (O'Kelly): 0.26;
1...c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 e5 5.Nb5 a6 (Lowenthal): 0.18;
vs. 1.d4:
1...Nf6 2.c4 d6 (intending Old Indian Defence, with ...Nbd7, ...e5, ...Be7): 0.29;
1...Nf6 2.c4 b6 (Queen's Fianchetto Defence - intending 3...Bb7): 0.29;
1...d5 2.c4 e5 (Albin Counter-gambit): 0.44 plus 2.Nf3 Bg4: 0.33;
1...d5 2.c4 Bf5 (Baltic Defence): 0.48 plus 2.Nf3 Bf5: 0.22;
vs. 1.c4:
1...b6 (or ...e6) intending 2.d4 e6 (or ...b6 - i.e. English Defence): 0.18;
1...Nf6 intending Old Indian formation: 0.29;
1...b5 2.cxb5 a6 (English Jaenisch gambit): 0.56;
1...Na6 (Lemming Defence - played by some strong masters, at least): 0.33;
vs. 1.Nf3:
English Defence-like formation: 0.29;
Hippopotamus formation (...g6 and ...b6): 0.56;
Old Indian formation: 0.29;
1...b5 (Reti Polish variation): 0.48;
vs. 1.g3:
Old Indian formation: 0.22;
1...d6 2.Bg2 c6 (possibly intending ...Bg4 later): 0.18;
1...h5 2.Nf3 b5: 0.52;
1...g5: 0.41;
White:
1.b3 (Larsen's Opening): 0.00;
1.f4 (Bird's Opening) -0.07[!];
1.e4 including: King's Gambit: -0.41[!], Closed Sicilian, main [6.Be3]: -0.11[!], Exchange French: 0.11, early Bg5 vs. Pirc/Modern: 0.22 each [with 3.Nc3], Exchange Caro-Kann: 0.07;
1.d4 including: Colle [vs. ...d5, with c3]: 0.00; Zukertort [vs. ...d5, with b3]: 0.07 (if 1...c5 then 2.d5 Nf6 3.Nc3: 0.33, 2.e3: 0.07, 2.c3: 0.00 and 2.dxc5: 0.11 all possible).
Finally, here's a link to an old chess.com thread re: underrated chess openings (seems to be a Class player discussion):
https://www.chess.com/forum/view/che...rated-openings