While there were fewer clubs for avantgarde and underground music, there were festivals.

Sunset Sound System, a legendary San Francisco electronic music collective founded in 1994 by djs and producers Galeno Amoroso, “Solar” Phillips and Justin “J-Bird” Brill, threw illegal parties in parks, beaches and other locations where they played house and techno music starting at sunset. These parties evolved in 2009 in the "Sunset Campout", a three-day camping festival in the mountains of the Sierra Nevada, quite different from the desert festivals of the Los Angeles area.

Burning Man inspired several other "desert" festivals, especially after Burning Man became "corporate" and a tourist attraction. However, unlike Burning Man, most of them eventually became electronic music festivals. Bosque Hrbek put together the Symbiosis Gathering in 2005 in the Santa Cruz mountains, later co-produced with Kevin KoChen (a speaker at the first edition), and typically aligned with celestial events. For example, in 2012 it was a five-day camping festival on Nevada Paiute land during a solar eclipse. In 2015 about 20 thousand people flocked to the Symbiosis Gathering, which had become an electronic music festival with some (curated) art installations.

The Center for New Music was co-founded by composers Adam Fong (CalArts class of 2006) and Brent Miller in 2012. It joined older venues like the Center for Contemporary Music at Mills College, the Yerba Buena Center for the Arts and Stanford University's CCRMA (Center for Computer Research in Music and Acoustics) that presented avantgarde music.

Veteran composer Paul Dresher continued to compose and perform music for custom-built instruments (i.e. sound sculptures) such as the "quadrachord" (2000) and the "hurdy grande" (2008). In 2009 he premiered "Schick Machine", an opera scored entirely for invented instruments (several built by Daniel Schmidt and Matt Heckert) with libretto as usual by Rinde Eckert and performed by Steven Schick. "Sound Maze" (2015) was a sound installation of twelve invented large-scale musical instruments, again mainly built by Daniel Schmidt.

The Polish-born pianist Jaroslaw Kapuscinski (UC San Diego class of 1997, at Stanford after 2008) became an audiovisual composer with musical performances that generated visual accompaniments like "Where is Chopin?" (2010), accompanied by synchronized faces of previous listeners as they listened to Chopin's music.

David Cope's computer program "Emily Howell" for music composition, conceived in 2003, went on to release the albums "From Darkness Light" (2009) and "Breathless" (2012).

The Italian-born neo-futurist Luciano Chessa (UC Davis class of 2004), who founded the Orchestra of Futurist Noise Intoners in 2009, defied all categorizations of classical music with works such as "Cena Oltranzista nel Castelletto al Lago" (2016), a 60-hours opera that required the cast to fast for 55 hours and ended with a banquet.

Many musicians pushed the envelope of digital music, showing what could be done with a simple laptop while incorporating methods inherited from musique concrete, electronic dance music and dissonant chamber music, resulting in albums such as "Down With The Scene" (2000) by Kid 606 (Miguel Trost-Depedro), "Lateral Forces - Surface Fault" (2001) by Kit Clayton, "Fell" (2002) by DJ Sutekh (Seth Horvitz) and "Tainted Lunch" (2005) by Safety Scissors (Matthew Curry).

Blevin Blectum (Bevin Kelley) and Kevin Blechdom (Kristen Erickson), two former Mills College students, collaborated on The Messy Jesse Fiesta (2000), credited to Blectum From Blechdom, and then released solo albums such as Blevin Blectum's Look! Magic Maple (2004) and Kevin Blechdom's Eat My Heart Out (2005).

Holly Herndon joined the ranks of digital songwriters who practiced convoluted cybernetic post-pop with albums such as "Platform" (2015), entirely composed on a laptop from vocal samples and synthetic sounds.

A crucial experience of underground hip-hop music was concocted by a group of White transplants who relocated to Oakland from different parts of the country: the Anticon collective, formed in 1998. Unlike gangsta-rap and other popular brands of ghetto hip-hop, Anticon catered to the White collegiates who preferred “conscious” rap. Sole (Tim Holland), the main brain behind Anticon, originally from Maine, released the first Anticon album, "Bottle of Humans" (2000), recorded not in a studio but in bedrooms, delivering an erudite stream of consciousness with punk fervor over a fluctuating layer of samples and live instruments. Alias (Brendon Whitney), also from Maine, was the introspective bard of "The Other Side of the Looking Glass" (2002). Then there was a trio who had met in college in Ohio, cLOUDDEAD: producer Odd Nosdam (David Madson) and rappers Doseone (Adam Drucker) and Yoni Wolf. Their albums "cLOUDDEAD" (2001) and "Ten" (2004) represented the artistic peak of the collective. Anticon stretch the genre in all directions. For example, Doseone fronted Subtle, a chamber sextet whose album "For Hero For Fool" (2006) had little in common with traditional hip-hop.

A prominent producer of breakcore was Xanopticon (Ryan Friedrich), documented on the all-instrumental album "Liminal Space" (2003).

Lil B (rapper Brandon McCartney) pioneered "cloud rap" with his numerous "digital" albums, starting in 2009.

The psychedelic tradition survived in the mostly-instrumental meditations of Six Organs of Admittance, the project of guitarist Ben Chasny, starting with "Six Organs of Admittance" (1998), in the "free folk" of Devendra Banhart, notably on the album "Rejoicing in the Hands" (2004), and in the "space-folk" of the guitar duo Barn Owl, starting with "Barn Owl" (2007). Santa Cruz-based foursome Comets on Fire played acid-rock with a punk vengeance on "Comets on Fire" (2000) and "Field Recordings From the Sun" (2002).

Loren Chasse, a member of the improvisational group Thuja which descended from Mirza, mixed improvised instrumental music and field recordings in projects such as the Blithe Sons, documented on "We Walk The Young Earth" (2003), and Of, authors of "The Sun And Earth Together" (2008).

Several acts contaminated punk-rock with funk rhythms, harking back to the disco-punk hybrid of the New Wave, notably Erase Errata, four riot-grrrrls who debuted with "Other Animals" (2001), Out Hud, hailing from Sacramento, with the all-instrumental album "Street Dad" (2002), and their offshoot !!! (pronounced "chik chik chik"), with the EP "Me And Giuliani Down By the School Yard" (2003).

The hyper-prolific James Ferraro was both a member of noise-makers Skaters, a purveyor of ambient music on "Last American Hero" (2008) and cosmic music on "Pixarni" (2010). His lo-fi instrumental album "Far Side Virtual" (2011), created with a software application and meant to be experienced on mobile phones as a library of ringtones, became a sensation and pioneered vaporwave.

The multi-faceted Sacramento-based percussionist Zach Hill contributed both the spastic instrumental post-rock of Hella's albums such as "Hold Your Horse Is" (2002) and "Church Gone Wild/ Chirpin Hard" (2005), and the confrontational hip-hop of Death Grips' "Exmilitary" (2011).

Sematary, the project of Sacramento's DJ Sorrow (Zane Steckler), further blurred the borders of hip-hop with the trilogy of "Rainbow Bridge" (2019).

Heavy metal too was derailed in multiple directions. Leviathan was the original "one-man band" (Jeff Whitehead) of San Francisco's black metal that later inspired many more individuals: a prolific derivative musician who evolved into the brooding philosopher of "Massive Conspiracy Against All Life" (2008). The duo Deafheaven fused black metal and psychedelia on the lengthy suites of albums like "Sunbather" (2013). Sutekh Hexen fused black metal and power-electronic noise on "Behind The Throne" (2012).