Hello. 
I'm looking for a new suggestions for identifying non-trending tickers and then a way to rank that non-trendiness by some function. 

Is ADX the best way to measure for this? 

For me, "non-trendiness" does not mean that a channel has to be tight. A channel can be wide over a period of time, and price can go all over place. 

Idea: Is there a way to set a linear regression slopline channel? This way, I could say that there would be very little slope over some interval, but that price would bounce around inside of it...

Thank you very much.

We can't actually recommend specific indicators or settings.

That said, checking for ADX being low should be a good way to check for not being in a trend.

There are all sorts of way you could write some sort of normalized linear regression slope formula.

But one of the simplest might be something like the following:

100 * (FAVGC50 / AVGC50 - 1)

The above is directional, but you could make it non-directional using the absolute value function.

100 * ABS(FAVGC50 / AVGC50 - 1)

As far as actually making a channel and making sure price stayed inside, that would probably result in a pretty complicated formula.

Hi, Bruce. Thank you very much for offering ideas around the problem. This is very helpful.

You're welcome.