Animals
Body
Colours
Food
Clothes
100
Hold your horses
wait a moment
100
Foot in mouth
To say something embarrasing 
100
Out of the blue
Without warning or unexpectedly 
100
A piece of cake
Something was easy
100
Wear the pants
To be the boss 
200
The elephant in the room
An issue that is avoided or not talked about
200
Get off my back
To leave me alone
200
Green with envy
To be jealous
200
Bring home the bacon
To earn a living or be successful
200
To tighten one's belt
To get by with very little money
300
Let the cat out of the bag
Reveal a secret
300
Cold shoulder
To ignore
300
Gray area
Something that is unclear or undefined
300
Cry over spilt milk
Being upset over something small
300
Feather in one's cap
An accomplishment that one can be proud of
400
Pig headed
To be stubborn
400
Play it by ear
To let things go as they will and see what happens
400
Green thumb
To be skilled at gardening
400
Take with a pinch of salt
To listen to a story with considerable doubt
400
On a shoestring
To get by with very little money
500
One trick pony
A person or thing with only one special talent
500
A finger in every pie
To have an interest or be involved in everything
500
White lie
A small lie that is told to be polite
500
Bread and butter
The job that supplies you with money to live OR basic things you need to survive
500
Wolf in sheeps clothing
A mean person who pretends to be nice