For Rocko, Men at Work's "Down Under" and Midnight Oil's "Beds Are Burning." Just Australian music in general would suit Rocko. Crowded House maybe.

For Swayzak, any and all tribal music. Saffri Duo all the way. It's because in my MCU level of lore surrounding him, he hails from a race of alien computer viruses called Phobians whose music is basically tribal music. He's a warrior with a fierce spirit. Tribal house music combined with what sounds like reversed Maori haka chants (because the Phobian language is basically reversed Maori, thanks to Swayzak having a New Zealander accent in the Trapped in Hyperspace game.)

For Space Ghost, new wave, because new wave was the sound of the future in the '80s, and Space Ghost comes from the future (right?) I can totally see Space Ghost loving some Devo or New Order.

For TOM 2, any punk rock from the early '00s would do. Nu-metal too. He has that free spirit, hotheaded teenager that's also dorky. The first Spider-Man soundtrack also suits TOM.

For Sabrina Spellman (animated series), the Spice Girls. What preteen girl around that era didn't love the Spice Girls? Only the albums from when Ginger was in the group, though. Forever is shitty.

Real music, not shitty music from the 90s and later

It was in the '10s music started to suck. Some music is good (Billie Eilish has so much talent, Doja Cat is pretty good), but the rest sucks. Kanye used to be a good rapper, then he collab'd with Lil Pump and felt so bad about it, he changed to Christian music.