This mod adds three new items based on risk/reward

Yin

For every evil...
Item pools: Devil, Angel, Treasure

Effects:
You can't hold soul hearts or black hearts
Sets your health to 3 red hearts
If you try to go over 3 hearts, then the game will remove the extras from you.
Gives you 4 random items
Makes you go down two floors every time you use a trapdoor
1/2 Tears
2X Damage

Yang

For every good...
Item pools: Devil, Angel, Treasure

Effects:
You can't hold red hearts
Sets your health to 3 black hearts
If you try to go over 3 soul hearts, then the game will remove the extras from you.
Gives you 4 random items
Permant curse of darkness
2X Tears
1/2 Damage

Yin Yang

...there is a choice.
Item pools: None
When you have both Yin and Yang, the game will remove them both and give you Yin Yang.

Effects:
12 Soul Hearts
Removes all curses
X2 Damage
X2 Tears

Showcase Video:
https://www.youtube.com/watch?v=XegUls8rHQ0