Andersen levellers, yes, love them. Way easier than figuring out how many blocks to use; just back onto them til the bubble says level. Now that DW knows how to set them, I don't even have to step out of the truck until unhitch time. A good solid $80 investment. The rest of the gear, not so much.
Rapid Jack is probably a good idea if you would change your own tire in the event of a flat - I never have changed my trailer tire. I just called CAA (AAA) for my last and only blowout (I have an RV+ membership). If I was really stuck, I would probably just use an Andersen leveller on the good tire and the tongue jack to raise the blown tire.
For the sand pads, I just use my old Lego block levellers that got pretty torn up by the last trailer.
Chocks, already had 4.
Not really sure what the dish drainer looking thing is for? Clean step? Like a door mat maybe?
Note: If you get the levellers, you will probably have to cut about an inch or so off the end to fit between the closer fitting axles on the Jay Feathers. The instructions are included for doing this, and it takes 5 minutes (and creates the purdiest pink plastic snowstorm). Cutting doesn't affect performance.
Another Note: $10 cheaper plus free shipping on Amazon if you do go for it.
2011 Jayco X19H (purchased 2015)
2008 Jayco 1007 PUP (purchased new, traded for the X19)
2012 Chev Traverse LT with TP