The song played over the bar fight is *NSYNC's "It's Gonna Be Me." In season 2's "Crossfire (2016)", Alex recounts how, after Kara arrived at the Danvers', she tried to mold Kara into a version of herself, but, realizing she couldn't, let Kara listen to "[her] own weird music," to which Kara indignantly retorts "*NSync is not weird. They are amazing."
The multiverse was confirmed on-screen (to the viewers) to still exist. However, it appears that the seperate Earths are now divided by something other than vibrational frequencies, as Brainy found no other Earths via the old method.
Actress Meaghan Rath, who plays the female Brainy, playing siblings with Jesse Rath on Being Human (2011) and is also his real-life sister.
In Superman: Brainiac Attacks (2006), Superman had to go into the Phantom Zone in order to find the Argonium 44, which would not only cure Lois and heal himself.
In the DC comics, the Anti-Life Equation is a theory developed by Darkseid after he learned of the Martian concept of the "Life Equation." Supposedly, the Anti-Life Equation mathematically proves that hope, love, and freedom are all meaningless and effectively destroys a person's free will. a transcendental mathematical formula originally said to allow those who knew it to dominate the will of any sentient race; this is the ultimate goal of Darkseid. Originally, it was said to have existed in the mind of "Billion Dollar" Bates, who took it to his death.