is there a keyboard available for my 12.9" 2015 ipad pro

Hello,

Here is the link to Apple's Smart Keyboard for iPad Pro 12.9-inch (1st Generation).

Smart Keyboard for 12.9-inch iPad Pro

You can also go out to Amazon.com and look at literally hundreds of options.

https://www.amazon.com/s?k=2015+ipad+pro+keyboard&ref=nb_sb_noss_1

You may also want to consider premium brands, such as Zagg, Logitech and Brydge.