David D and his Advanced Dating Techniques program is underrated, imo. A lot of it was him modeling and taking people's content who were much better than him and displaying it for everyone to see (plus a lot of his own stuff with octopus mating sequences mixed in, lol).
Real World Seduction is a great program too.
Both of them have a really heavy focus on attraction techniques though. So I'd be careful about that since, while it's very important, a lot of guys get stuck in attraction, especially when they're first learning it and end up coming off as a total asshole and only attracting really low self-esteem women because they're so heavily focused on using attraction techniques (yes, I've been there).
I'm not sure if you can even get any of the Love Systems stuff anymore... or the old school Mystery Method materials but they are both very good. I personally prefer the way push/pull is explained in the Love System's materials more than RWS, but that's me.
Sinn has some really good stuff... His 5 minute chemistry program has good stuff, same with his daygame program and some of his sexual stuff... he's known for overgaming though, so be aware of that.
Also, I don't know if you can still get Captain Jack's stuff or not but he's a legend with his sexual framing stuff.
Ultimately, you'll just need to get information that you find that resonates with you and then go and extensively field test it... everything, imo, is person dependent. Your looks, personality, confidence, style, voice, ethnicity, height, sense of humor, and a bunch of other factors, some you can do a lot about and some you can't do much about... all will determine how effective or ineffective something is for you along with the woman, her looks, self image, emotional state, attraction to you, what country you're in, her ethnicity, etc.
IMO, the most important thing that a guy can learn is social calibration... which takes lots and lots of trial and error, testing, finding out what works for you, being in set a lot, getting blown out, testing your limits and boundaries, etc.
Alright, I'm done.
I have a wonderful book I got online that helped me a lot in my relationships. You can chat me up if interested
Why don't you just say what it is so that we can all see what you're talking about... that way we can publicly judge you for your choice in books.