Trinkets have two modes: passive (bonuses for taking trinket to the equipment) and active (when you use trinket).
Passive - slowly regenerates health.
Active - heal self and allies.
Passive - all enemies have chance to drop coins.
Active - all enemies worth extra coin.
Passive - increases player health.
Active - shield player from damage.
Rift Defender Trinket
Passive - increases rift points.
Active - stun all enemies.
Trap Reset Trinket
Passive - traps reset faster.
Active - reset all traps for mana cost.
Passive - deal bonus damage when low on health.
Active - spend health to activate berserk mode.
Mana Rage Trinket
Passive - higher mana capacity.
Active - mana regenerates quickly for a short period of time.
Passive - resist stuns.
Active - break other players out of stun and briefly grants stun immunity.