"Now Sound" is admittedly the most unwieldy section within my own idiosyncratic filing system, and I continually second guess certain choices within this section.
The short answer would be post-Beatles pop, easy listening, film scores, and jazz - records made by aging composers, arrangers, and jazz & easy listening artists tuning in and turning on to the styles, moods, and vibrations of today.
But the section extends into a lot of tangential musics, including certain soul/funk, spiritual jazz, and world music. Anything that could be played during the party scene in Beyond the Valley of the Dolls or the sex scene on the money-covered circular bed in Danger: Diabolik could potentially qualify.
Please note that the default is not the year of release but rather the style. For example, a 1980s solo piano George Shearing record would go in the jazz section, but the 70s MPS record where he does "The World is a Ghetto" goes into the Now Sound section.
Anyone's version of "Soul Makossa" goes in this section, because every version of that track I've ever heard sounds like a wild 70s party at which I'm scratching at the window to get invited to, but the door never opens.
Hope this helps.