Alternative Paper

Stone Paper
100% tree free paper is a natural product manufactured from calcium carbonate.
http://www.stone-paper.com.au/

Favini, "Shiro Alga Carta"
Shiro Alga Carta began life as a way to use the damaging algal blooms of the Venice lagoon
http://www.favini.com/graphic_specialities/en/shiro-prd-21.php

Tree Free Paper
Taken from the website http://treefreepaper.com/treefree101.php

There are four different tree-free fiber sources from which paper can be made:
1. Agricultural Residues*
Examples: Sugar cane husk (also called ""bagasse"); Cereal straws – barley, oat, wheat, rice, rye... Husks and straw left in the fields after harvesting of the main crop.  Integrated with soil management, this represents an enormous resource opportunity worldwide.
*TreefreePaper.com believes this to be the most environmentally beneficial source for paper fiber. Your purchase makes use of an existing waste stream and there is plenty of it. As well as providing a diversion from virgin pulp, you are helping to eliminate the greenhouse gas pollution from what would otherwise be burned in the fields!2. Fiber Crops (also called On-Purpose Cropping) Examples: Hemp, Kenaf, Jute and Flax… These are crops planted and harvested specifically for their fiber and require dedicated tracts of land and agricultural inputs. It could play a roll in responsible eco-agriculture on a large scale, eg. Rotating kenaf with corn, soybeans or wheat. There exist dedicated proponents of these methods and TreefreePaper.com will continue to support these eco-pioneers by promoting their efforts as market efficiencies develop. Stay tuned.
3. Textile and Cordage Wastes Examples: Cotton linters after ginning for textiles, cotton and linen scraps, old rope… Already being used in specialty papers, currency, letterhead and, although good, does not represent a large opportunity for additional tree fiber diversion.
4. Wild Plants Examples: Wild grasses, Sisal, Bamboo... These are some of the oldest and most beautiful types of paper made and are produced primarily on a small scale.

Alternative Fibre Paper
Legion Paper
http://www.legionpaper.com/category/2011/7/26/alternative-fibers.html

Banana Paper 
specializing in Coffee Paper, Mango Paper, Hemp Paper, Sugar Paper and more!
http://www.ecopaper.com/

Hemp paper http://www.thehempshop.co.uk/product-239.htm

Somerset printmaking 
100% cotton, acid free & archival
http://www.stcuthbertsmill.com/st-cuthberts-mill-paper/somerset-printmaking/technical.asp

Hahnemühle 
appears to be at the forefront in terms of producing a bamboo fine art paper