As in one that sorts cards into custom headers? To do so add a # and the category name (capitals matter for sorting) after each card while editing the deck, so it looks like
1x Rampant Growth #Ramp
And then, when you set the deck’s default view to custom, rampant growth and everything else with #Ramp will be under a header labeled Ramp.
January 13, 2020 8:17 p.m.
If you have a category name that has a space in it such as Win Condition then replace the space with an underscore.
1x Blood Artist #Win_Condition
January 14, 2020 2:02 p.m.
There's also a setting while editing to make Custom the default view when looking at the decklist