Which objects are atomic in Mathematica?

Question

I am looking for a full list of atomic objects in Mathematica (for which AtomQ yields True).

I know about

Symbol
String
Integer
Real
Rational
Complex

SparseArray
BooleanFunction
Graph

Are there any others?

ref: http://reference.wolfram.com/mathematica/tutorial/BasicObjects.html

EDIT: Continually adding new symbols from answers to list above.

Answer 1

It appears your list needs one more object to be complete:

In[520]:= f = BooleanFunction[30, 3];

In[521]:= AtomQ[f]

Out[521]= True