This page should help newer players understand what exact cards are new and campaign-related, with the rules to accompany them.
Lord of the Rings LCG print and play guides/help
Overarching “Campaign” Rules in the Revised Core Set rulebook [Page 30 of this PDF]
MPC printing guide (Reddit)
LOTR LCG printing guide (ALEP)
The revised edition has some misprints, here is an official list of errata/corrections
Card Backs (Official and ALEP)
Revised Core Set Campaign Rule Cards (Bleed)
Revised Core Set Campaign Cards (Bleed)
[Mendor has an encounter card back]
Dark of Mirkwood Campaign Rule Cards (Bleed)
Dark of Mirkwood Campaign Cards (Bleed)
Hall of Gondor 
