I sometimes use my iPad as a second screen – an auxiliary display for alerts (if you're a masochist) or side-channel apps (to do lists, calendars, Pomodoro timers, etc). If you've got a smart cover you can use it as a stand, but otherwise you have two choices: buy one, or make one. I made one – or actually two. One for home, one for work.
I started with a design on Thingiverse and made some minor changes: I altered the slot size to work with 5mm Perspex and extended the rear feet because I was worried about the stand's stability. After a few rounds of trial and error on the laser cutter, I got a snug fit and a working stand. I used some scrap Perspex for mine, so there are some small cut-outs on the bottom edge.
If I were doing this again I'd either make the rear leg rounded so the notch wasn't supported with such a thin bit of Perspex (Perspex shatters easily) or make this out of something like MDF or ABS. I've used this stand for over a year on a daily basis and it's not failed in use, but I did drop one and the foot broke at the narrowest part. I'd also consider raising the iPad a little further off the desk, so you could charge it in a portrait orientation.
My main use case for this these days is to display Concentrate! while working, though I've also used it to keep an eye on the news at times of civil unrest and media inquisitions.