There's a truth though in this idea of honesty about materials that transcends a particular architectural fad, and I think brutalism ought to be an element that any design considers: can a structure be inherently beautiful without additional adornment?
I wish for more examples I could point to as brutalism that aren't just exposed concrete. The only one that springs to mind is this[0] redesign of some post-war brutalist (of the exposed concrete variety) playground equipment. It isn't a big step forward, but it's something. I also think that things allowing like good cable management to be seen is a form of brutalism. Actually, given this post's theme of "eco-brutalism", I think something like the earthship[1] might be a better example of brutalism.
[0]: https://www.assemblestudio.co.uk/projects/the-brutalist-play... [1]: https://en.wikipedia.org/wiki/Earthship
There is an example of a "brutalist" brick house in the Wikipedia page: https://en.wikipedia.org/wiki/Villa_G%C3%B6th
I live in a cool old concrete factory in Brooklyn that was haphazardly converted into lofts back in the nineties, and more recently purchased by developers to convert into "luxury" lofts. The conversion consists mostly of throwing a cheap wood veneer over the floors, carpeting in the hallways, newly painted drywall over various surfaces… I had never thought of the building as particularly "brutalist" before, but I lamented the covering of the worn concrete.
"If people didn't want to live in an old factory… why would they move into an old factory?" I keep asking myself.
Fortunately — believing these changes are upgrades — they haven't changed much for the residents that they didn't manage to evict, so my unit is still honest. And since it has an east-facing-window, it's even covered mostly with plants, like these photos :D
Even in wikipedia, the general definition is there but obscured. Despite nearly every pictorial example in wikipedia featuring exposed concrete (as well as reddit's r/brutalist), any material can be found in a brutalist design. It must merely be exposed and accepted for what it is. e.g. wood shown to be wood and allowed to warp, decay, or even grow, as opposed to being overlaid with drywall. Stones not just in a foundation or a garden, but in a living room. This honesty and connection to materials is in contrast to the "dominating" sense of "brutalism," of which cheap government buildings are often twisted up in.
Though the pictures on wikipedia are misleading, certain quotes from the page are worth reading. Specifically when brutalism is described as "an ethic, not an aesthetic".
And also: "Peter Smithson believed that the core of brutalism was a reverence for materials, expressed honestly, stating "Brutalism is not concerned with the material as such but rather the quality of material",[33] and "the seeing of materials for what they were: the woodness of the wood; the sandiness of sand."
Source: wikipedia and have lots of architect friends.