I like the spool holders from the “Prusa Enclosure V2 - MMU2S” from @OndrejStritesky , because they are compact. They didn't have an easy way to hold the PTFE tubes to the spool holders.
This model clips in to the hexagonal features of the spool holders and has to flex quite a bit to make it fit, so print from PETG or some fairly flexible filament. I included an end cap and a bolt recess for a 3mm x 12mm fastener that can be used to tie all the mounts together if you want. Mine are very secure without them, so I'm not even using them. The arm holds an M5 PTC coupler.
Update 12Feb2024, added version for PC4-M10 PTC.
The author marked this model as their own original creation.