User chclau on YCombinator's Hacker News posted a great link to VHDL related materials. Then a reccomendation was made by Ben Rudgers to make it a GitHub/md file. Done.

VHDLReadersList.md

Eight free (and legal) FPGA/VHDL books

By chclau on YCombinator's Hacker News

There are lots of free resources on the Internet to learn. Here I list eight legally free VHDL books. Some of the sites require registration to download the free book.

• MicroZed Chronicles (Vol. I)
• Free Range VHDL
• Altera's FPGA for Dummies
• Xilinx's High Speed Serial IO
• FPGA prototyping book
• FPGA's now what
• The Zynq book
• Introducing Spartan 3E and VHDL