The Libby8dev website covers some simple computer designs including Libby8 itself, but is mostly about the DIY 8-bit computer:
FIGnition is an educational DIY computer which you can buy, easily build, write simple programs directly on it and importantly: understand from end to end. All you need is £20 and some simple soldering equipment - that's all I used to develop it in the first place! FIGnition is like an early 80s microcomputer: it only has 8Kb of RAM (expandable to 32Kb) and 384Kb of storage. It uses 3 chips and only 46 components. It is powered by USB and uses USB to upgrade the firmware, so FIGnition will improve over time. It runs a variant of FIG-Forth. Find out more from here.
PhorsePOV is a simple POV gadget which uses a single button to enter messages in Phorse code (a variation of Morse code centred around a phone keypad layout to make it easy to learn and remember). It's based around an ATTINY25 AVR running from its internal RC powered by a Lithium coin cell strapped to the back. The stripes version is shown on the left, followed by an actual build. PhorsePOV is available to buy.
Libby8 is (or rather, will one day be) a minimalistic Z80-based Hobby Home Computer inspired by Grant Searle's build your own computer articles and the realisation that an Atmel AVR is fast enough to function as a microcontroller-based ULA (an early Gate Array). Libby8 can be build using easily available components: A Z80 CPU, an Atmel AVR, 32Kb of SRAM, 512Kb of serial Flash and some additional descrete components. The hobby board is a veroboard design constructed using Stripes, a fast stripboard design program written in java.
The above shows a potential PCB mockup and an in-progress stripes design for the PCB.