A moratorium is in effect on adding information from Fire and Blood until December 20th.
From A Wiki of Ice and Fire
|Coat of arms||A brown fret on white (Argent, a fret brunâtre)|
|Seat||in the northern mountains|
House Stark (AGOT)|
House Baratheon of Dragonstone (ADWD)
A Dance with Dragons
House Knott at the end of the third century
There are no known Knotts mentioned during the timespan of the events described in A Song of Ice and Fire.