H2O!

Caddy is a web server like Apache, nginx, or lighttpd, but with different goals, features, and advantages.The purpose of Caddy is to streamline an authentic web development, deployment, and hosting workflow so that anyone can host their own web sites without requiring special technical knowledge.

Cherokee is a flexible, very fast, lightweight Web server. It is implemented entirely in C, and has no dependencies beyond a standard C library. It is embeddable and extensible with plug-ins. It supports on-the-fly configuration by reading files or strings, TLS/SSL (via GNUTLS or OpenSSL), virtual hosts, authentication, cache friendly features, PHP, custom error management, and much more.

Hiawatha, a secure and advanced webserver

G-WAN is the fastest available Web server on Windows and Linux.

Lwan is a high-performance & scalable web server for glibc/Linux platforms.