I use concrete in various forms. I gave up using wood as it rots, attracts termites & carpenter ants .... so concrete is my material of choice!
Cinder block raised bed that I painted blue and also painted the concrete pavers to match:
I use concrete wall blocks to create more raised beds:
I like rocks for raised beds, but way too expensive to purchase here in flat FL. So I decided to use bags of concrete that I stacked (I did a little at a time) to make a "rock" raised bed:
And if I need a shallow raised bed, I use concrete borders:
It does require some muscle to lift some of these materials, but it's basically permanent once it's down! I love concrete!