I wanted a way to run a chain from the extruder to the hotend that would work with dpetsel's Bullseye duct (https://www.thingiverse.com/thing:2759439). I started with sandpit's Cable Chain Extruder Mount and modified it to give the extruder lever arm more room to move. I narrowed and replaced the mounting point he used with one of johnniewhiskey's chain links so that the fitment is now perfect. Then I added an additional chain mounting point courtesy of hanananana's modified extruder mount. Finally, I adjusted hanananana's modified hotend mount so that it will work with the Bullseye duct. I also made sure that the chain will be level on both ends.
Update
• 2019.03.18: After seeing two people post that he had issues with the length of the mount being too short for their particular setup, I have added two longer versions.
Versions
• The normal length should work for most people. The z axis screw lined up perfectly on my Ender 3.
• If the normal version doesn't line up for you, I have added a +1.5mm and +3.0mm length…

Combined right mks gen l  from https://www.thingiverse.com/thing:3688967
with drag/cable chain connector from https://www.thingiverse.com/thing:3690894
Update:
Added the Fusion 360 file, it's just the imported STLs did the "Mesh to Brap", cut the not required items away.
And some images of my installation, I thing I have some Over Extrude going on.
I had some grinding to do to make the 2 cases join and the lids are verrry tide.
I guess I have to make/print a straight  bed chain connector too it looks a bit bend.
Have Fun