Taking about mechanical pencils, people often hear about big names such as Uni, Pentel, Faber Castell etc. But in fact there are lots of many small business who has unique designs. What they do is manufacturing customized barrel and classical insert (such as Schmidt or Pentel P20x), as a result, we can have some nice metal/wooden pencil instead of commercialized plastic mechanical pencils.

Here is a list of these manufacturers that I know, and this list will be updated whenever I know someone new :

QwerkTools – Heavy Brass Pencils

Toms Studio

S.T. Dupont Line D Medium Mechanical Pencil Black

Blick Studio

Nicolas Hemingway : simple cylindrical design, not really something standout but if you want to metal alternative (also fiber carbon and wood), go have a look.

Modern Fuel

Before Breakfast – Made in England

Everyman Grafton

Meister by Point

Manufactum – Made in Germany

IJ instruments – Very pricey and very solid pencils.

LRD

Parafernalia – Their Revolution Pencil is very uniquement, and this design has something to do with the Centre Pompidou architecture in Paris.

22designstudio – They have concrete body mechanical pencils. Pretty cool.