I'm trying to think if Heaven's Gate was an outlier or perhaps the peak of a trend at the time. I'm wondering if these 90s cults were even prevalent or perhaps that was pop culture reflecting the shock of Heaven's Gate
I think you'll be interested in my answer to the question:
In short, I say Heaven's Gate was something very new, almost unprecedented.
As for was the group well known before they committed suicide, no. While they did have a few incidents of media coverage going back to the 70's, they were also barely known in the town they lived in (compare that to Scientologists in Clearwater, FL, Rajneeshees in Wasco County, OR, or Jim Jones's the People's Temple in Northern California, so-called Fundamentalist Mormons in Utah and surrounding states, and Aum Shinrikyo in Japan, all of which were reasonably well known locally before they became international news). By the 90's, the group had only a little over three dozen members, and before their suicide, were probably about as well known as the Branch Davidians before their stand-off (that group was two or three times larger than Heaven's Gate). Nothing like the Westboro Baptist Church in terms of notoriety, and probably less well known than several other UFO Religions are today, like the Raëlians. The Heaven's Gate group were covered by a handful of media outlets, including the LA Weekley, and appeared in at least two books about UFOs and UFO religions. But all in all, pretty obscure.