Marking cables using heat shrink tubing is probably the most effective, reliable and professional looking solution there is. The video above is an example using a Brother P-Touch E550W and a heat gun. Producing these types of labels really is as fast as it looks in the video.
Other printers that can print heat shrink tubing includes the most Labelstations, Dymo XTL & Rhino Pro, most Brady and the Brother E300 & E550W.
Coloured heat shrink can help identify groups of cables while printing on the tubing can identify individual cables.
Using heat shrink instead of cable flag labels improves identification as it is less cluttered improves and airflow for enclosed areas such as server racks.
Using the heat shrink tubing instead of cable wraps improves identification from as wraps can accumulate mucky adhesive. Cables wraps, much like flag labels, require more effort to apply than heat shrink tubing.
The only down side to heat shrink tubing is that it can only be applied to cables that do not already have a bulky plug on the end. As you can see from the video it is best for this type of cable marking to be applied to cables that haven’t yet been terminated.