One of BP’s own promoted trading systems uses ADX as a filter but is not actually based on the ADX, but might be worth a read. The system is basically a 1-hour MA crossover with fixed TP/(trailing)SL.
HLHB trend-catcher system
I don’t comment on whether this system is worth adopting or not, but its results are published weekly.
I have also been exploring this same indicator as a filter in the same way with my own daily charts and am finding some value in its presence there - but I have not come to any definite conclusions yet worth talking about on BP.