Sacrifice Cheats:

To enter a cheat, press Ctrl+Shift+~ on your keyboard. The cheat menu will appear. Type in @ with a space after it, then the cheat, then Enter to confirm the cheat.

alliwantforxmasisa [Name of Creature] = One of that Creature

aplethoraof [Name of Creature] = Four of that Creature

gimmegimmegimme [Name of Spell/Creature] = Adds that Spell/Creature Summoning Spell to your Spellbook

ihavethepower = full Mana

castratetheheathens = Ability to pick up Heathen (red) Souls as though they were Atoned (blue) Souls

yourbulletscannotharmme or mywingsarelikeashieldofsteel = Invincible Wizard

timeisonmyside = Fully recharged Spells

Heroes:

Having these powerful Creatures on your side almost guarantees victory. You can get Heroes without cheating, but it's hard. And, since you're cheating anyway, who says there can only be one of each Hero?

Toldor (Ent)

Sirocco (Dragon)

Sara Bella (Brainiac)

Gangrel (Scythe)

Astaroth (Scythe)

Lord Surtur (Storm Giant)

Gammel (Ikarus)

Faestus (Pyromaniac)

Thestor (Gnome)

Also, there is one Creature that is not a Hero, but also cannot be accessed normally: the Dragon Hatchling. It is a tiny, flightless baby Dragon without the "Breath of Life" special ability or the "Grasping Vines" innate ability.

You can also use the "Plethora" and "Xmas" cheats to get your own personal Farmers, Peasants, and the like.