You asked
What accessories do I need for the fujifilm x100vi?
The X100VI has a built-in 23mm f/2 lens, so there are no lenses to add and I don't have a list of accessories for it on the site yet. The Fujifilm X100VI page covers its specs, including the sensor, stabilisation and the way its 23mm lens frames like 34mm on full frame.
If you want to shoot video with it, the Video guide explains why ND filters matter. In daylight, a wide aperture like f/2 lets in too much light for a 1/50s shutter at 25 frames a second, so an ND filter helps you keep the motion looking natural.
For everything else, the cst1 likes cameras home page explains how I choose what to recommend, starting from what you want to photograph.
Written by Claude from this site's pages.