Pull requests VERY welcome!
AnoNet is a decentralized friend-to-friend network built using VPNs and software BGP routers. anoNet works by making it difficult to learn the identities of others on the network allowing them to anonymously host IPv4 and IPv6 services)
BitMessage is a P2P communications protocol used to send encrypted messages to another person or to many subscribers. It is decentralized and trustless, meaning that you need-not inherently trust any entities like root certificate authorities. See whitepaper
The Drogulus (WIP) is a programmable peer-to-peer data store. It's an open, federated and decentralised system where the identity of users and provenance of data is ensured by cryptographically signing digital assets.
eDonkey network is a decentralized, mostly server-based, peer-to-peer file sharing network best suited to share big files among users, and to provide long term availability of files
GNUnet is GNU's framework for secure peer-to-peer networking that does not use any centralized or otherwise trusted services.
Grimwire is a browser OS which uses Web Workers for process isolation, and WebRTC for peer-to-peer communication.
I2P is an anonymizing network, offering a simple layer that identity-sensitive applications can use to securely communicate. All data is wrapped with several layers of encryption, and the network is both distributed and dynamic, with no trusted parties.
Kademlia is a distributed hash table for decentralized peer-to-peer computer networks
NameCoin is a decentralized naming system based on Bitcoin technology.
Nightweb connects your Android device or PC to an anonymous, peer-to-peer social network. You can write posts and share photos, and your followers will retrieve them using BitTorrent running over the I2P anonymous network. It is still experimental.
Osiris is software for decentralized portal, managed and shared via P2P between members.
PeerCDN automatically serves a site's static resources (images, videos, and file downloads) over a peer-to-peer network made up of the visitors currently on the site.
PeerServer is a peer-to-peer client server using WebRTC, where your browser acts as a server for other browsers across WebRTC peer-to-peer data channels.
Project Meshnet aims to build a sustainable decentralized alternative internet. Used by Hyperboria and built on CJDNS.
RetroShare is an open source, decentralised communication platform. It lets you chat and share with friends and family, with a web-of-trust to authenticate peers.
The Serval Project lets mobile phones make phone calls to each other peer-to-peer without a base station.
Syndie is an open source system for operating distributed forums offering a secure and consistent interface to various anonymous and non-anonymous content networks.
Tavern is a distributed, anonymous, unblockable network designed to ensure that no one is silenced, censored, or cut off from the rest of the world
Telehash a new encrypted P2P JSON-based protocol enabling developers to quickly build apps that are distributed and private (see v2 of the spec)
Tox The goal of this project is to create a configuration free p2p skype replacement.
Unhosted - also known as "serverless", "client-side", or "static" web apps, unhosted web apps do not send your user data to their server. Either you connect your own server at runtime, or your data stays within the browser.
Vole is a web-based social network that you use in your browser, without a central server. It's built on the power of Bittorrent, Go and Ember.js. Uses bittorrent sync.
BitCoin is a digital currency, a protocol, and a software that enables it. Decentralized crypto-currency
LiteCoin is a peer-to-peer Internet currency that enables instant payments to anyone in the world (was based on Bitcoin)
PeerCoin/PPCoin is the first known cryptocurrency based on an implementation of a combined proof-of-stake/proof-of-work system