The new Helium blockchain whitepaper is very interesting to me, because it uses what is called Proof-of-Coverage and Proof-of-Serialization instead of proof of work as a verification method.  I look forward to seeing some proof of concepts using this technology for IoT.

Helium Blog
https://blog.helium.com/tagged/blockchain
https://blog.helium.com/tagged/blockchain

Helium Whitepaper
http://whitepaper.helium.com/
http://whitepaper.helium.com/