What documents are required for a 1-year marriage extension visa in Thailand?

Bank statements for last two months need to be signed by someone at the bank. They will do this at your bank no problem.

Also be aware you will need an update in your bank book for the morning you go confirming the money is still in the bank.

Everything else is covered by other peoples reply’s.

Once immigration have all your docs they will come to your property within 14 days. At this point you need two different neighbours to confirm you live at that location. They will take a copy of their Thai ID as well. Then immigration will take photos of you all outside the property.

Adding to what you already listed, you will also need a copy of the house book your wife is listed in. A new passport size photo for the application. If you rent you will need a copy of your lease, with the name of the rental on it (most are generic and don't have the property name on them). You will need a copy of the owner's Thai ID card, and a copy of the house book they are listed in. You will need a copy of your passport ID page, the page your visa is on, the page your entry stamp is on, and any extensions you have had. A copy of you 90 day report receipt, your entry card. You will need pictures of you and you wife outside where you live, so you can see the name, or number. A picture in front on your door if it is a condo room showing the room number, and at least two pictures of both of you inside your apartment. You will need a hand drawn map showing how to get to your location from the closest major road. That is basically it, but each office might want more. I copy every page in my passport just to be sure, as in the past they have always found some other page they wanted. We just did my extension last Friday and am now on my under consideration 30 day wait, for the fifth year at Chiang Wattana. Also, there are two documents for you marriage. One is the certificate, and the other is your marriage registration. You need a set of the originals the first time. You should have gotten two sets when you got married at the local Amphur.

Go to the immigration office you intend to use. Take your wife. Ask for the list of requirements required by that office. Follow the list and you should be good. As all the different offices have slightly different requirements, it would be a waste of time posting here what's required in Phang Nga if you live elswear.