Hey Sarah - I am also preparing to take the MCE, and have found the below resources that Kristen Carmean has prepared to be extremely helpful.  Good luck to you!

Sample Questions for MCE Exam: Admin & Operational

Sample Questions for MCE Exam: Analytics & Reporting

Sample Questions for MCE Exam: Lead Lifecycle

Sample Questions for MCE Exam: Program Fundamentals

Sample Questions for MCE Exam: Targeting & Personalization