One of my greatest bits of luck was getting access to these and other Unix workstations&servers as a teen.

If you run old SPARCstation OSes, a few points of interest...

If you get the OpenWindows era with Open Look look&feel, one of the things that were newish around then is the pinnable menus and dialogs. You could sometimes tear off a menu and turn it into a persistent window that's more like a toolbar (which was also emerging then).

Open Look (or Sun) was also introducing small rectangular drag&drop target widget on windows, when drag&drop was new. Which I don't recall seeing later, so maybe it was a mix of less drag&drop than we thought we might have, and more an expectation of the user to learn what things could be dragged and where they could be dropped.

Behind Open Look also a number of different toolkits and window system backends that might be behind a given Open Look application and desktop. My favorite toolkit was XView, and it was very easy to work with in C, and used varargs sorta like GTK later did. Desktop-wise, besides X, there was the XNeWS server, which supported a kind of display PostScript on steroids, and you could write entire applications in PostScript (though their OpenLook widgets looked poor early on, compared to the pixel-perfect XView result).

Maybe the key thing to notice about OpenLook... At the time, the other main X GUI look&feel that workstations were moving to was Motif, which was mostly just rectangles. Someone once posted screenshots of a dialog in Open Look and then another in Motif, with all the text removed, and, in Open Look, you could pretty much tell what all the familiar widgets were, and you immediately knew how to interact with all of them. That was considered valuable at the time. (Though HCI in general has moved more towards brochure-like and magazine-like motivations in the interests of the creator, and away from motivations we had before, for new-user and power-user usability in the interests of the user.)

If you go back a little further with your workstation, to SunOS 4.1.x or 4.0.x, you can forget about X and NeWS, and see something a bit different: SunView. This was a monochrome GUI, maybe sorta like an old Mac, but without all the things the Mac had, and backed by much more sophisticated workstation/server OS. People did powerful things with it, on a workstation with a megapixel display and 8MB of RAM. The GUI toolkit was the predecessor to XView, and similar.

For workstation application programs (like my employer developed), it wasn't unusual to implement your own portable GUI layer, including an entire window systems. So, our stuff and Interleaf's, for example, would create a native window for whatever workstation desktop was in use, and implement our own desktop within that. And they were all different, and often innovative, sometimes in ways that have been lost.

I didn't see how all the different CAD, EDA, etc. packages worked, but sometimes the workstation was pretty much an appliance for running a single program, and on occasion would even be branded with a physical badge for the application software on it.

You can rediscover some of the same flavor still alive by looking at UI innovations by, for example, Blender, where (last I used it) they built UI from scratch, and they seemed to innovate in the interests of the users, including power users. Maybe more accessible to us on HN, some IDEs are places that get creative innovations often in the interests of power users.)

You'll also see innovations less-familiar in some other workstations, like Apollo Domain. (A lot of Sun stuff might be a little too familiar, because they sorta won, albeit in the form of Linux and the BSDs today. SunOS was also arguably the easiest out-of-box platform for building GNU-ish software on the Internet, before Linux was sufficiently ready, so that's another regard in which they both influenced and were influenced.)

Also, if you end up trying a real-metal vintage workstation experience, don't forget to hit the degauss button on your 21" CRT, be startled by the sounds and the ray behavior, and each time wonder in the back of your mind whether there's any health risk to be standing near it each time that happens. :)