Haproxy - Reliable, High Performance TCP/HTTP Load Balancer
Kemp LoadMaster - L4/7 Load Balancer w SSL offload
CroxyProxy - CroxyProxy is the most advanced free and secure web proxy.
Avi Vantage Load Balancer - Avi Vantage is a suite of multi-cloud application services that, among others, consist of a Software Load balancer to help provide you with a scalable, quick, and secure application experience.
goproxy - Proxy is a high performance HTTP(S), websocket,TCP, UDP, Secure DNS, Socks5 proxy server, TLS.
AWS Elastic Load Balancing - Amazon ELB automatically distributes incoming application traffic across multiple Amazon EC2 instances in the cloud.