The Interplanetary File System (IPFS) is a decentralized network protocol for sharing hypermedia in a distributed file system. IPFS can be used to link blockchain transactions This effectively timestamps and secures the content, without having to put the data on the chain itself. Filecoin, an IPFS-based decentralized storage cloud, is closely related with the IPFS protocol, and provides the incentive system.

Nethereum is an open source .NET integration library for Ethereum. It is designed to help developers easily integrate the Ethereum blockchain into their .NET applications. It consists of modular libraries for features that are covered are writing smart contracts, cryptographic wallets, DApps, and managing blockchain data.

Ubiq is an Ethereum fork that aims to create a more stable smart contract platform for building DApps. Ubiq's protocol currently uses a Proof-of-Work (PoW) consensus mechanism, but will switch to Proof-of-Stake in 2019. The network is powered by the UBQ coin.
Ubiq's goal is to create a reliable and stable platform for developing DApps by modifying Ethereum's code base with important changes that will make it more secure and reduce instability. Consensus is based on their Flux Difficulty Algorithm, which is designed to constantly adjust the hash rate to protect against network attacks.