1. *Title Deed*: A Title Deed is the most important document as it gives details of ownership, rights, obligations, and mortgages on the property. This document should be clear and marketable, and it is prudent to get it checked by a lawyer. Also, you should verify it at the local municipal office and confirm whether the property is registered and stamped by the respective Registrar.

2. *Builder-Buyer Agreement*: This contract details the obligations of both parties, the amount to be paid by the buyer, the dates of payment, and the action taken in case of failure to pay by the buyer. Before signing the agreement, go through the document carefully. Ensure the clauses mentioned in the contract are as declared during the purchase of the flat.

3. *Encumbrance Certificate*: An Encumbrance Certificate is needed for the period during which the property was held by the seller. It is necessary to ensure the property is not mortgaged and is free of legal dues or complaints.

4. *Occupancy Certificate (OC)*: When a builder constructs a building, he must get a clearance certificate from the local administrative bodies in terms of safety standards met. This certificate is called the Occupancy Certificate. Getting approval from the municipal authorities means the building has complied with its rules.

5. *Certificate of Compliance*: This certification ensures adherence to approved plans. Requesting the approved plan from the builder is wise. This will not only help ascertain if the construction is carried as per plan but also help in case of future deviations from the approved plan.

6. *No Objection Certificate (NOC)*: NOC from various bodies such as Electricity, Water, Environment and so on ensure a hassle-free and smooth transfer of property.

7. *Completion Certificate*: Upon completion of the construction, the builder needs to get a Completion Certificate from the municipal authorities signifying adherence to safety standards, approved plans. Without this certificate, it's hard to get the OC.

8. *Sale Deed*: A parent document, this certifies the legal owner. Unless there is a Sale Deed, the property buying process is incomplete.

9. *Allotment Letter*: Issued by the builder, this document is crucial as it carries details about the flat, the price, the payment made, construction schedule, house plans, delivery date, and the builder's liability in case of any delay.

10. *Tax Receipts*: A crucial document that includes records of the last tax paid on the property, it's essential to confirm that the taxes for the property are up-to-date.

In addition, depending on the area and type of property, other documents may also need to be checked. These can include conversion certificates (for agricultural to non-agricultural land), building plan approvals, physical survey, and layout plans, amongst others. While this list of documents seems extensive, it serves as an essential checklist when purchasing a ready-to-move flat. It is crucial to verify each of these documents and take help from legal experts if required. Remember that it is better to be safe than sorry - due diligence conducted before the purchase can save significant headache later. Moving into your new home should be a joyous occasion - do not let it be dampened by legal troubles.