Cyclone is a low-level network toolkit that provides support for HTTP 1.1 in an API very similar to the one implemented by the Tornado Web server. It has localization based on gettext with pluralization support, native support for XMLRPC and JSONRPC, native support for WebSockets (drafts 75 and 76), decent support for sending plain text or HTML email with TLS and attachments, built-in support for Redis, and support for HTTP authentication.
Zato is an Enterprise Service Bus (ESB) and app server written by pragmatists for pragmatists. It provides an HA load-balancer, hot-deployment, and hot-reconfiguration almost everywhere (forget server restarts). It has a browser-based GUI, CLI, and API (forget XML configuration). It supports many protocols, industry standards, and data formats, including HTTP, JSON, SOAP, REST, AMQP, JMS WebSphere MQ, ZeroMQ, Redis, SQL, and FTP.
Vedis is an embeddable datastore C library built with over 70 commands. It is similar in concept to Redis, but without the networking layer, since Vedis run in the same process of the host application. Unlike most other datastores (e.g. memcache, Redis), Vedis does not have a separate server process. It reads and writes directly to ordinary disk files. A complete database with multiple collections is contained in a single disk file. The database file format is cross-platform; you can freely copy a database between 32-bit and 64-bit systems or between big-endian and little-endian architectures.