I bought some of the mounting clips (so that I'm not only relying on the adhesive backing to stay up) and the heat shrink butt connectors from Amazon because it was cheaper. I needed extra wire to get from the ends of the outer 2 strips to the driver. I bought end caps, silicone sealant and some other connector related items because I was splicing 2 strips into 3.
If you're not planning on wiring the driver directly, you probably need something to wire a plug onto the end.
Bottom line, beyond the light strips and the driver, almost everything else is pretty situational, and therefore optional.
I should add that I ended up having the contracter that built the deck/sukkah structure install the lighting, but we're talking handyman, not electrician.