Nice, I like that as a DIY case!
I use a bag by kiefer neu. It fits the deck saver, all the cables I need. Small folding headphones and even a nintendo switch (or pocket operators).
I’ve made this out of 8€.
Wood, stickers, paint and nails, whatever included.
The Roland 808 travel bag fits remarkably well, and has thick padding plus a long strap that slings over the shoulder.
Nothing beats Boowoo’s case:
Expensive but well worth it.
I use the OP-1 Glide case by Analog Cases
https://analogcases.com/collections/teenage-engineering-cases/products/op1-glide-case
I use a Roland case for an Organelle, thinking of getting another one for the OP-1 - seems like it’ll easily fit the Deck Saver, for extra knob protection. There’s more than enough room for cables, etc. I’m still using the cardboard case it came in, though 
I use a piece of leather with paracord stitching up both sides great wallet style soft case , also acts as dust cover … easy to make yourself and looks expensive… lol