The easiest filter is to look for parties where alcohol and drugs are banned, and latecomers are not allowed.

I go to play parties regularly, but only go to ones that are constructed in a manner that encourages enthusiastic consent and safety.

Those parties and connections are not for normal people, more like 1%.

The kinds of parties being described aren't all that unusual for the bay area. It's certainly not isolated to tech.

Meet interesting people, network. You'll figure it out eventually.

That aside, they can be fairly inclusive.

I got involved in the community in 2002. I was a typical dot-com nerd. I'd been doing some amateur rocketry events in the black rock desert and had heard about Burning Man. Eventually, I decided I had to go. Got introduced to a group of people that had a camp, they discovered I was terribly useful (I could weld, machine, fix electronics, repair generators, build things, etc), and the rest was history.

I went, met a tremendous number of people, cultivated lots of friendships and from there became privy to all the other inter-related things happening in the bay area, including the kinds of parties described above. The debauchery I've had the opportunity to participate in is quite extensive.

Be useful, be nice, be non-judgmental, go meet people, get involved, do stuff, become part of the community and you'll enjoy similar opportunities.