A series of source books for D&D 4E by Sceapture Games.
From the introduction of one of the books:
This is a series of PDF-only source books intended for use with the Dungeons and Dragons™ 4E Role Playing Game. To save production and printing costs, they are produced in greyscale where possible, and can even be reproduced two-up on a single A4 sheet in booklet style (if you’re struggling, do get in touch with Sceaptune Games). Powers are produced separately, in colour, so they need not be printed out with the main booklet. If you would like to use anything printed here in your own supplements for Dungeons and Dragons 4E, do get in touch.