That is a very informative and well written post Teoh. Bravo!
Here is my colour selection in order to get an idea of how different can be our colour selection.
I paint mostly portraits and botanical illustrations and I have two palettes made mostly by primary transparent colours, made mostly by Rembrandt or by raw pigments that I make into watercolours . My studio palette has 23 colours and my minimal urban sketching one has just 8 colours.

Here is the list of the full studio palette.

Lemon Yellow PY184
Transparent Yellow PY150
Lemon Yellow Titanate PY53
Transparent Yellow Oxide PY 42 ( transparent ochre)
Transparent Yellow Medium PY128
Azomethine Yellow PY129

Cobalt Green PG 50 ( by Sennelier)
Ercolano Blue PB31 ( made by raw pigment)
Cobalt Blue PB28
Smalt Blue PB32 (made by raw pigment)
Phthalo Blue GS PB15:3
Indigo ( mixed by PG7/PV19 i magenta)
Indanthrene Blue PB60

Pyrrole Red PR264
Pyrrole Orange PO71
Q. Magenta PV19 i
Q. Rose PV19i i
Q. Rose Magenta PR122
Cobalt Violet PV14

Purple mixed by PV55 and PB32

Transparent Red Oxide PR101
Raw Umber Hue PY42/PR101
And Sepia mixed by PG7/ PR264 + PBr7 B. Umber.

The minimal one has the following colours.
Transparent Yellow Medium PY128
Azomethanine Yellow PY129
Pyrrole Red PR264
Pyrole Orange PO71
Q. Rose Magenta PR122
Transparent Oxide Red PR101
Smalt PB32
Phthalo Blue GS PB15:3