good machine. But you should probably have asked first as we wuld have recommended the qidi x pro instead. Essentially the same machine, but with wifi, removeable bed and touchscreen - and a little cheaper.
Things you will probably need:

Sanding blocks
set of mini files, diamond or metal, both work well.
Don't know what print surface they currently use but some cheap gluesticks wouldn't hurt either.
Digital calipers - essential !
Join the flashforge creator pro facebook group :-)

Have a look at openscad for making models.