It's so easy to walk in to your local JB or drone stockist and then end up on the black air hole of Amazon or eBay and buying pointless stuff you don't need, and that's just a waste of time and space.
There's somethings you possibly don't need and other things you do need, in all honesty and I am going to try and break some of that down for you right here, right now.
Landing Gear, to help and aid in landing the drone off the ground - if you mainly fly in parks and paved areas around the traps, it's possibly not too important however for some one like me who flys over bush land and down the bush, landing gear helps me avoiding to land on the dirt and that's always a safe option in all honesty.
Screen Protectors - Yes it would be nice to have a screen protector on it, in all honesty - however these might not be needed, I generally am one to not rock something techy with out a screen protector but I have been doing that with this while I have been scared of damaging the screen, I am yet to do so and that's definitely a good thing in all honesty.
I ended up as a solution picking up PGYTECH RC COVER this allows the screen to be protected by the cover while the remote control is being carted around with your drone.
ND Filter, Neutral Density filters are one of the biggest black holes you can go down the rabbit hole with, especially if you don't understand the science behind a ND filter, and the settings you need to achieve the best results with the ND filter. So unless your experienced and willing to put in the time with ND's I think that's a black hole that a lot of drone pilots could avoid.
There's plenty of cases, skins, remote controller sticks and more out there that are in theory just quick little cash grabs for no reason, like the Fly More Kits either the basic or the advanced are a must purchase in my mind as the additional batteries provide more flight time and allow you to spend more time in the sky and that's a win win.