My favourite door mat is a very plain, flat one for outside and I have bought several online that are advertised as getting the dirt off your feet always!
It works to a degree and they are small-ish squares with a fairly long pile.
A off-cut of Carpet, that had been over-locked all the way around.
I bought it for $10.
I have a dark colour.Go for (dark greys or browns).
It is rectangular, you find them at Carpet stores...and it works SO Well!
Mine is on the outside of my front door.
one 1 of my sisters gave me for a birthday present, a long time ago, with 10 red tulips with green stalks & leaves on it! The tulips are starting to wear off a little bit now. We also have a plain brown 1 in front of the tulip mat, so we don’t scrub out to much of the tulip pattern!!!