As far as I know:

Invest contribution in a tech and something will rise per tech level you invested.

Bestiary: 5% experience increase for killing monsters in the wild per tech level; You gain more experience when you kill monsters.
Noblisse oblige: 5% credit increase on killing monster in the wild per tech level; you gain more credits when you kill monsters.
Devoutness: 10% increase when using shrine per tech level; You gain more coins and credits when you use shrine i.e. your gems are worth more in shrine.
Win-win: 10% increase for guildfund and contribution per tech level Your investments will lead to more contribution and more gain when you claim from guild.
Mr. Popularity: 5% discount when doing blacksmith per tech level; Your blacksmith investment will cost less coins.
Loyalty: 10% reputation bonus when gaining reputation per tech level; you gain more reputation in events like ragnarok, banish, or when you attack in arena or in the wild.

This is as much as I know, please add or correct if I am wrong somewhere.