The best MCCQE question bank depends on what you need. If you want additional independent question practice, CanadaQBank, AMBOSS, Ace QBank, UWorld, and QBankMD can
MedCognito is the stronger primary option if you are preparing specifically for the MCCQE and want structured teaching combined with MedBuddy by MedCognito for question
For most candidates, especially IMGs, the best approach is not free or paid. The best approach is: Free official MCC resources + MedCognito for structured