In Aotearoa, our main org is Dayenu - New Zealand Jews Against Occupation. Here's the Facebook group for Jewish people (including Jews who are reconnecting or actively in the conversion process!). You can read about the founder here if you want to get a feel for it first.
Sh'ma Koleinu – Alternative Jewish Voices (NZ) is now also merging with Dayenu. But they'll be maintaining their blog still here.
Internationally, the most reputable orgs I'm familiar with are...
Jewish Voice for Peace in the US.
If Not Now also in the US.
Kavod which is in Boston in the US.
Jews Against White Supremacy which is fairly new and based in the US.
Tzedek which is an explicitly anti-Zionist synagogue in Chicago in the US.
Chavurah For A Free Palestine at Kehilla Community Synagogue is a pro-Palestinian group in Piedmont, California in the U.S.
Judaism on Our Own Terms in North America.
Independent Jewish Voices in Canada.
Loud Jew Collective in Australia.
Jews Against Fascism in Melbourne, Australia.
TzedekUKI covers both the UK and Ireland.
Een Andere Joodse Stem - Another Jewish Voice is in Belgium.
Shabbes 24/7 Collective is also in Belgium.
Tsedek ! Collectif juif décolonial is in France.
Junts - Associació catalana de jueus i palestins is in Catalonia.
Jüdisch Antikolonial is in Switzerland.
Jüdische Stimme is in Germany.