As thetime wrote, Way out west, Oya festval and:
Flow Festival (Finland)
Summer Well fest (in Romania, so it's close)
Frequency (about a week after Sziget in Austria, only sharing a few names though these years)
Grape Festival (Slovakia during Sziget)
Lowlands (sharing a few names with Sziget)
Thanks for the tag, @Gnomicide! And thanks so much for your kind words, @flump — it's messages like yours that make the whole project worth it. I won't be slowing down on it anytime soon, there's still so much to add! You're the best, thanks again.