Looked into this.
OE seems to be Onlyencodes. They're closed now and you need profile screenshots from two other private trackers to apply. Sucks that FNP shut down so abruptly. I especially feel for anyone who donated.
A4K seems to specialize in 4K content which doesn't interest me
Couldn't figure out what DP refers to. Maybe Decoder.lv? Not found.
Seedpool was open as of yesterday. Good luck y'all
Thanks for clarifying. It sounds like my understanding of open is different than yours. I've always thought open meant you could register an account without an application process. It sounds like you're saying open means you can apply without an invitation.