I'll try to touch on many of the points described here with an example of what I use to label Systainers.
The white, printable PVC cards that fit the Systainers are nominally 86mm x 54mm. The matte Festool label covers, 497855, are labeled as 85mm x 55mm, yet when measured with a dial caliper they are actually 86mm x 54mm go figure?
I use Bodno white PVC cards purchased on Amazon. Photo 1
I use Online Labels OL5030WJ white, matte, weather proof labels for an inkjet printer.
https://www.onlinelabels.com/templates/blank/ol5030
Online Labels offer 6 different templates to aid in designing the labels. I prefer to use Maestro Label Designer.
Each label is designed separately and can then be added to the template for printing. I'll usually print 8 labels (1 sheet) at a time. Each label is scored on 4 sides for easy removal. Photos 2 - 4.
Finished result photo 5
These labels can be removed in 1-piece from the PVC card or from the Systainer. If any adhesive remains, it can be removed with a quick wipe of Goo Gone on a paper towel.