Activating this trainer:
If not state otherwise below, press F1 at main menu.
Listen for 'Trainer Activated'.
Press desired hotkey. All hotkeys can be changed on the trainer.

Promo Options:
NumPad1: Reset Horror Gauge

Trainer Options:
NumPad1: Reset Horror Gauge
NumPad2: Monsters Don't Attack

Editor Options:
Character Stats: Current HP
Character Stats: HP Max
Character Stats: Current Vigor
Character Stats: Vigor Max
Character Stats: Combat Stat
Character Stats: Sleight Stat
Character Stats: Merchantry Stat
Character Stats: Awareness Stat
Character Stats: Overwatch Stat
Character Stats: Max Inventory Capacity
Character Stats: Current Flourish Meter
Character Stats: Max Flourish Meter
Currency: Current Hellion Currency
Inventory: Current Amount of Selected Inventory Item

Notes:

EDITOR OPTIONS

For Character Stats, mouse over the portrait of a character in your party or an enemy and the values will fill in.  Edit the value, then press TAB to set it.

For Hellion, open the inventory to see the current amount you have and the value will fill in the editor and you can edit it.

For Inventory Item, click an item in the inventory and the amount of the item you have will be shown in the editor and you can edit it.

Reset Horror Gauge:
Toggle on and while active when you move into new areas the gauge will reset.

Monsters Don't Attack:
Toggle on and most enemies will not attack you when it's their turn.