The "Independent" knot is a part of the "UK Fibre Supplier" line.
These fibres are from the company that has been supplying the world's oldest shaving brushes (est. 1919) from the UK with both badger & synthetic fibres for 40+ years now.
The name is very much a nod to fibres used in their inexpensive line of synthetics, as the fibres come from the very same source.
These fibres are known for having a good scrub to them without being scratchy, something that's absent in a lot of synthetic knots. The fibres are also soft when lathering and can almost get "crunchy" when drying, another unique element to these knots.