http://snap.stanford.edu/data/

Stanford Large Network Dataset Collection

• Social networks : online social networks, edges represent interactions between people
• Networks with ground-truth communities : ground-truth network communities in social and information networks
• Communication networks : email communication networks with edges representing communication
• Citation networks : nodes represent papers, edges represent citations
• Collaboration networks : nodes represent scientists, edges represent collaborations (co-authoring a paper)
• Web graphs : nodes represent webpages and edges are hyperlinks
• Amazon networks : nodes represent products and edges link commonly co-purchased products
• Internet networks : nodes represent computers and edges communication
• Road networks : nodes represent intersections and edges roads connecting the intersections
• Autonomous systems : graphs of the internet
• Signed networks : networks with positive and negative edges (friend/foe, trust/distrust)
• Location-based online social networks : Social networks with geographic check-ins
• Wikipedia networks and metadata : Talk, editing and voting data from Wikipedia
• Twitter and Memetracker : Memetracker phrases, links and 467 million Tweets
• Online communities : Data from online communities such as Reddit and Flickr
• Online reviews : Data from online review systems such as BeerAdvocate and Amazon

SNAP networks are also availalbe from UF Sparse Matrix collection. Visualizations of SNAP networks by Tim Davis.