Adventurer's Addendum 1 contains three classes and 14 feats that introduce new and unique mechanics into any Pathfinder game.
Artificers are those who study the magic of item creation and enhancement, specializing in magic of warding, physical creation, or physical alteration. Knowing the entirety of their large but niche spell list, artificers change the battlefield to support their allies and cage their foes. Skilled crafters and item creators, artificers also learn to use and make alchemical and magical gear to greatly expand their options.
Seers are experts at manipulating and reading the strands of fate to predict events before they occur, and either change them or ensure they happen. Rather than standard magic, a seer instead uses special powers focused around divinations and manipulating fate. A skilled seer will need to predict the events of battle before they happen in order to manipulate them to their greatest advantage.
Wardens embody nature's pure, unbridled strength. By tapping into wild forces, wardens are able to control their forms and shapeshift at will, turning into all sorts of natural creatures - and unnatural chimeric or elemental beasts - customized to the needs of each individual warden. Their connection to nature also provides them with a variety of powers, allowing them to command elemental forces or heal the wounds of their allies.