Voids
These can be used after the customer has left and the same transaction has been rendered void by the clerk. The money is still in the register and will have to be removed either then or towards the end of the shift.

No Sales.
These are the most common suspect sales. There are legitimate reasons like correcting change mistakes but if the clerk is performing "sweet hearting", pilfering, void transactions or substitute scanning, towards the end of a shift they will have to remove the accumulated money before their shift ends. Therefore it is especially important to check for all no sale transactions within the last hour of a shift.

Returns / Refunds.
These are usually questionable when an exchange is made and cash is being paid out. Items are pulled from stock and fictitious refunds are given to friends relatives or the clerk themselves.

X / Z reads.
X Reads may be taken by fraudulent clerks who over charge customers or omit items and keep the money in the register until the end of the shift. They will then do an X read and compare the value with the amount in the register and remove the surplus. This results in the register being correct at the end of the day, the clerk giving the excuse they were taking their tips that they kept in the register.
Z Reads may be taken early in the day to reset the register. All the takings so far are pocketed by the clerk, resulting in the owner only getting the takings from that point on.