Yo! 
~Got another handy Lua script tool for anyone interested. For several large projects, I often found myself turning to Robin’s (@x42) “Send Tracks to Bus” script, for adding Aux Sends to selected tracks, routing them to a new bus that it would create. That tool is very quick and definitely handy, but no doubt limited in scope… -because sometimes (for example) the bus you want to route to already exists within the session.
So, to help with editing efficiency and eliminate the incredible tedium of having to use Right-click → New Aux Send… every time I need to add a new Aux Send to/from a group of tracks/buses (‒as well as then having to set each to 0 dB, one-by-one…), I spent a couple days here writing and tweaking a much more capable tool, yet one that’s still quite simple and straightforward:
Aux Send Router
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In a nutshell, Aux Send Router allows you to add Aux Sends to/from one or more selected tracks/buses to a track/bus of your choosing, including a new one. ( → Only works for Ardour 9.0+ by the way, and maybe(?) the latest Mixbus.)
Features:
- Supports audio and midi tracks/buses.
- Select from all available existing tracks and/or buses in the session.
- Route from the selected track(s)/bus(es) to a new or existing bus.
- Route to the selected bus(es) from a new or existing track/bus.
- Prevents self-routing/feedback situations.
- Conveniently set the send level (in dB) you want to use for any new Aux Sends created.
- Automatically saves the session just before Aux Send creation, just in case something goes wrong.
And here’s an example .gif (…moving slow on purpose so it’s easier to follow along 
):
Anyway, hopefully this’ll help others out there save some time editing/routing as well, ‒especially when working with large and ‘complicated’ projects… 
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Also, if you were wondering why anyone would use Aux Sends instead of direction connections, look no further than here — straight from the German horse’s mouth!: On Delay Compensation & Recommendations for Routing
~Enjoy! 
-J