I think SureScreen UK are also working on a biodegradable Rapid Antigen LFT. It's due for release soon.
https://www.lovebusinesseastmidlands.com/love-business-news/2022/02/08/surescreen-to-launch-biodegradable-covid-test-cassettes/
Note - the Rhinoswab isn't biodegradable. (I don't think any swabs are biodegradable).