Is there a list or database of standardised projections (that can be applied in d3.js) used to create "nice-looking" maps of invidiual countries (e.g. UK, France, Germany) or geographic regions (e.g. Europe, Middle East or North America)?
e.g. in this mapping tutorial for the UK, the author uses the projection
var projection = d3.geo.albers()
.center([0, 55.4])
.rotate([4.4, 0])
.parallels([50, 60])
.scale(6000)
.translate([width / 2, height / 2]);
Are these values a standard set used by many map-makers to display the UK, or did the author find them by trial and error?
Whilst it's useful to have these values for the UK, no further projections are given for other countries in the world. Do other countries have standardised map projections which map-makers tend to use, for instance set by national mapping agencies e.g. the Ordnance Survey?
Most of countries have their own geographical reference system, often several. In France, for instance, we use or used 3 of them: NTF, ED50 and WGS84.
However, there is no official projection and every cartographer produces its own map with its favourite projection. Of course, some projecions may more suitabe for some countries. For instance, you won't use Mercator's projection to map the south pole... but otherwise you're rather free to use whatever please you or what conveys your message.
Anyway, at small scale (i.e. country-wise), most of the projections will agree.