All the Mini flight accessories I've got are mothballed until the crazy weather we've been having here in the Mohawk Valley of NY turns to Spring. I'm talking primarily about high winds, but also snow.
A lot of people would agree that the Mini flies better in wind without any extra weight so when I do fly at present it's completely naked. The drone that is, not me. Accessories I did get and do use were a spring loaded landing pad which I use a lot, a hood that clips around the camera & gimbal for controlling side light falling on the lens when the sun is lower in the sky, undercarriage extenders, and a range extender mirror thingy. All of these seem to work well.
Mac OS software. I bought a Final Cut Pro X license after running the free trial for a month. During that time I got far enough into it to reach first base. My main goal with drones is to create publicity for our farm and products. Working with FCPX tends to keep me thinking more like a film maker when practising flying, planning flights, watching the FPV in real time, & when reviewing clips later.
iOS software. UAV Forecast I'm finding to be accurate and indispensable. I shelled for the annual license to get the extended forecasts.
Things I'll be getting soon include a set of filters, ND- and an ND/CPL, and a big external directly-attached drive for storing clips and FCPX projects. Currently I'm offloading clips to our Synology NAS. The NAS doesn't support mac OS tagging of media files which I think is essential for getting clips organized in FCPX. The NAS is also a tad slow for heavy media applications. It works though.