graph-tool is described as 'Graph-tool is an efficient Python module for manipulation and statistical analysis of graphs (a.k.a. networks)' and is an app in the Development category. There are four alternatives to graph-tool for Linux, Mac, Windows and Python. The best alternative is neo4j, which is both free and Open Source. Other great apps like graph-tool are RedisGraph (Free, Open Source), NetworkX (Free, Open Source) and LemonGraph (Free, Open Source).
RedisGraph is a property graph database module for Redis. It is the first graph database to use linear algebra on sparse adjacency matrices to implement graph operations, which lets it achieve high performance. It understands OpenCypher queries.