Thinstation is a thin client linux distro using std. x86 hw. It can boot from network, pxe, syslinux, CD, floppy or flash-disk and connect to servers using VNC, RDP, XDM, SSH, Telnet, tn5250, tarentella, 2X, NX, Thinlinc, VMWare VDI or ICA.
openthinclient is an open source thin client solution
openthinclient is a free open source thin client solution consisting of a Linux based operating system along with a comprehensive Java based management GUI and server component. It is intended for environments where a medium to large number of thin clients must be supported and managed efficiently.
CULT is an Open Source software-only network bootable thin client Operating System that provides a complete solution for thin clients, PCs or virtualized hardware.
DIET-PC (DIskless Embedded Technology Personal Computer) is a software kitset enabling IT professionals to build an open source GUI appliance based on commodity x86 (PC), PowerPC (Mac) or ARM (handheld) hardware, using an embedded Linux methodology.