What are resources available to everyone both inside and out of the military to help develop lower enlisted into good leaders/NCOs?

You're reading a bit too much into it. Leadership isn't something that can be learned from a book. While books about Leadership can be bought and read...remember that those books were written by people that used their leadership style. Their style might not be a good fit for you. Not saying don't read them as there is usually good advice in them...what I do recommend is that you take every single Leader you have had since you joined the military...think about every one of them and pinpoint their good traits and their bad traits....then take from that and create your own leadership style. Or, in other words, be the Leader to others that you want leading you.

Two pieces of advice for you, and of course this is only my opinion.
1. MSG (Join to see) gave you the best advice about leadership you may ever get "be the leader to others that you want leading you" ... this logic and advice was said to me years ago and I have held true to it in all I do; both civilian and military.

2. Your experience with leadership is weigh heavily on your expectations and where they are derived from. What I mean by this is, your perception of what a leader is does not define what good or bad leadership is. You may think a person is not leading you properly, without really understanding everything that they are doing.

I am a VP of Ops for a private company and I am an NCO (Sq Ldr) in the National Guard. I use different approaches to both of those jobs as they require it; however my style of leadership does not change. I tend to lean more towards servant leadership; how can I help others develop and grow. There is no magic book, but rather trial and error. I was never a good leader until I understood empathy. I would recommend educating yourself on what your leaders are actually responsible and accountable for, and redesign your expectations from there.

SPC (Join to see) Your eyes and ears are your resources. Listen closely and observe the behavior of excellent leaders, then mimic their words and actions.