Neu! were my gateway drug. What a band.
I'd recommend the German version of Trans Europa Express, the big three classic Can albums (Tago Mago, Ege Bamyasi, Future Days), Can's debut Monster Movie, Deluxe by Harmonia, Faust IV, Yeti by Amon Düul II … actually, definitely check out Faust IV, that's an unmissable record.
If you're interested in immediate influences and successors, can't go wrong with early Captain Beefheart from the late 60s, or early Fall records from the early 80s.