I have gone down the rabbit hole so far down it's not funny.
Posting here might raise more question and more option than a mind can deal with.
After trying most units on the market (my profile list them), I settled on the SansAmp Para Driver DI which is a good DI, a powerful EQ and a natural sounding distortion that is reminiscent of a B15 pushed a little hard. The pedal has some added features such as the ability to take out booming bass (a knob labelled as Rumble filter) which I find myself using quite often.
Many moons ago a Sans Amp representative posted on this site that the SansAmp Bass Driver DI distortion sounds like a pushed SVT and that the SansAmp Para Driver DI sounds more like a B15 distorting. That is right on the money as far as I am concerned.
The Para Driver DI gets little attention, particularly compared with Dark Glass offerings, but it's a useful hidden gem in my book.