Are any commercial plastics made from biomass/plant matter?
The original answer only gave a link to a commercial bioplastic producer.  The answer has been edited to provide more information.


Yes there are.  Here is an example: Biome Bioplastics

European Bioplastics (an industry group) estimates that the global production of bioplastics was about 2 million metric tonnes in 2017.  They forecast that this will increase to almost 2.5 million metric tonnes by 2022.Source 

One estimate puts the market value of bioplastics at around 6 billion USD in 2018 and growing to almost 15 billion USD by 2023.  Source

Common sources of bioplastics are starches (like corn), cellulose and aliphatic esters. 

Commonly, bioplastics are used to make compostable/biodegradable packaging and films, as well as disposable cups and utensils.