Some sellers like the Minelab Go-Find so much that they have started producing separate accessories for it. See the photos: a backpack for Minelab Go-Find plus a control box cover.
I hope the price for this backpack isn’t more expensive than that of the detector. From the experience: cases for large musical instruments are perfectly suitable for transporting a detector. The only thing is that it looks strange: you are walking through the wood and there is a parti-colored saxophone case on your back ))