A whiteboard. Costs a penny and pays a fortune. Or a bunch of whiteboards. Cover the walls in them. And pens (of course, lots of colours) and other things t

A whiteboard. Costs a penny and pays a fortune. Or a bunch of whiteboards. Cover the walls in them. And pens (of course, lots of colours) and other things to stick to them, like Lego bricks with sticky bottoms (workflow/queues), and post-it notes (that are able to stick to whiteboards, a lot of post-its can't), and a countdown timer for your huddles so they don't take that little bit too long, and multiple small screens stuck there too if you have workflow or queues. And a webcam permanently on if you have a remote employee/partner 'visit' the office on-demand but don't record them because they're likely working from home and they'd like their home privacy. All of these, and more, are cheap, simple, tactile, and can be mixed around until you find something that fits.