You can get/put ideas for what should be on the cheat sheet here.
Axioms of probability (finite spaces, infinite spaces)
Sequential and continuous probability models
Properties of probability laws
Conditional probability
Independence
Conditional Independence
Random Variables
Probability mass functions
Common random variables (Bernoulli, binomial, geometric) and how they come about
Functions of random variables
Mean and Variance, and their properties
Joint PMFs of more than one random variable
