In case it helps anyone, this is what I submitted (copy-pasted from my cover letter):
1. Duly filled and signed Form G-1450 authorizing $680 Credit Card Payment towards Filing fees (Form + Biometric).
2. This Cover Letter.
3. Duly filled and signed Form G-1145 requesting e-notification for acceptance of application.
4. Duly filled and signed Form I-751
5. Copy (Front and Back) of Permanent Residence Card
6. Copy of marriage certificate
7. Evidence of the Relationship:
i. Exhibit A – Joint Occupancy of Communal Residence.
This includes Lease documents, copies of IDs showing same address, examples of mail to both being received at same address and preparations for future joint home ownership (mortgage preapproval, buyer agency agreement and communication with realtors).
ii. Exhibit B – Financial – Joint Bank Account Statements. We submitted all monthly statements for all joint bank accounts.
iii. Exhibit C – Financial – Tax Returns.
iv. Exhibit D – Financial – Retirement and Insurance.
This includes Retirement, Life Insurance and Disability Insurance plans showing each other as beneficiary, and joint health insurance
v. Exhibit E – Other Evidence of Union.
This includes Nabeela and Greg listing each other as their emergency contacts, bill showing joint mobile family plan, joint amazon household and health documents providing evidence of plans to have a child together.
vi. Exhibit F – Evidence Related to Wedding Day and Personal and Family Interaction. (This was over 200 pages, but very well organised description of events, trips etc over the last 3 years, and supported by photos, hotel bookings, flight tickets, family zoom calls, snapshots of family group chats etc.)
vii. Exhibit G – Affidavits from Spouse's mother and Petitioner's sister.