As in, bands that have vocalists, but they aren't singing any lyrics. Think something like Early Obituary, or early Cryptopsy to a certain extent.

Anything but slam, please. Thanks in advance!

Pan.Thy.Monium?

It's progressive death, though...

Even though most of their lyrics aren't available, they do in fact have lyrics.

Japanese technical death metal insanity by Impending Annihilation.

https://www.metal-archives.com/bands/Im ... iscography

From promo mail: "With the overarching goal of perpetual motion in mind, Impending Annihilation has crafted a sonic experience that refuses to stand still. Describing their vocal approach, vocalist Horizon points out that they don't adhere to traditional lyricism in their music. Instead, they view vocals as instruments themselves, using growls and gutturals in the same way one would incorporate sweeps and tappings into a song structure."