As a knottyer who does decorative work mostly I have to add a few other knots.
In fancy work the workhorse practical knot is the constrictor knot, it can be used in many places and will often used just temporary but can not be missed in those circumstances. And it is the starting knot for one of the Turks Head knots too, the 4 lead, 3 bight TH can easily be started our of a constrictor.
An other knot in which the practical and decorative work meet is the carrick bend, and mostly the full or double version, which is also a start for a TH, the 3 lead, 4 bight TH. It can also be used as a base for the Lanyard knot (also known as the 2 strand Diamond knot or Chinese button knot.)
And one of the most tied practical knots, the sheetbend, also has decorative vallue, in netted lace.
Willeke