Customize transaction saved search to display the custom field of a custom record type

This is done by creating a new field from the record type, where the Field Type = List, List/Record = Transaction, and Record is Parent box must be checked.

Create an additional custom field on the record type:

1. Navigate to Customization > Lists, Records, & Fields > Record Types.
2. Click the name of the Record Type.
3. In the Fields tab > Click New Field button.
4. Enter a name in the Label field.
5. In the Type field, select List/Record.
6. In the List/Record field > Select Transaction.
7. Record is Parent box must be ticked. 
8. Click Save.

Create the saved search utilizing the custom field:

1. Reports > Saved Searches > All Saved Searches > New.
2. Select Transaction as the Search Type.
3. In the Results tab, look for the name of the Record Type in the joint fields.
4. Select the custom field and click Add.
5. Click Save & Run.