If you need to look up a rule quickly during a match without carrying heavy books, the tabletop community uses several legal, free platforms.

Games Workshop no longer sells standalone, official rulebook PDFs. They use a closed digital ecosystem to protect intellectual property and streamline balance updates.

These remain the efficient backbone of your list, offering speed and objective control. Key Strategies in the New Codex PDF

More importantly, from a hobbyist’s perspective, relying on a pirated PDF has massive downsides:

Games Workshop updates Warhammer 40k rules regularly through digital and physical releases.

The Complete Guide to Warhammer 40k Imperial Knights Codex Options

For players looking to move beyond standard matched play, the book also introduces robust narrative rules. The system allows players to run Crusade campaigns where their noble pilots pursue personal deeds of legend, developing their pilot’s oath and characteristics as the campaign progresses.