The major contributors to SBNR are very numerous. No-one has yet identified them all. Summarising their contribution would be practically impossible.
And there is no definite “product” of their endeavours, no nice Nicene “result”. One could spend days trying to give the gist of Gebser, Yogananda, Jung, or Huxley. Their modern heirs Stanislav Grof, Lawrence LeShan, William Irwin Thompson, or Glenn Morris would require just as long.
Anyone can wander the SBNR canon and pull out a personal conversation, a particular mind. With no official version, no orthodoxy. With no orthodoxy, no borders. SBNR is what you make it, not what it makes you.
Still, SBNR is no longer as directly indebted to Romanticism. It is leaner, and it has learned the difference between posturing and effectiveness. It has passed through existential crises and been tempered by them. What we have now is a settled growth of many intertwining plants — and a definite opportunity.