fmtlog is a performant asynchronous logging library using fmt library format. It's easy to use and might be the fastest C++ logging lib so far.

Previous link was pointing to a code.google.com repository, which
reported a 404 error.

New link seems to be not official, but working ;)

yaml-cpp is already listed on libhunt, adding it to the Yaml category here

There is not a Yaml parser listed here, although there is one on libhunt

add C++ for full name.

Workflow, C++ Parallel Computing and Asynchronous Networking Engine.

paiza.io has multiple files supporting with collaborative editing.

CUDA is a richer, though vendor-specific, alternative for working with GPUs - with several entries in this list already. And while it lets you write modern C++ code on the GPU side - its host-side API is C-style, clunky and annoying. cuda-api-wrappers makes it awesomely-C++'ish.