Michael Gruhn Audio has released Tiny Piano, a free virtual piano instrument for Windows.
A very small piano VSTi. It’s tiny – what more do you want? … it also sounds OKish.
Tiny Piano is available to download as a freeware VST instrument plugin for Windows PC.
More information: Michael Gruhn Audio
This piano instrument does not have a GUI, nor parameters to control the sound, but I find it sounds surprisingly good with a bit of reverb on it.