A box of rubber bands (if your wing uses them for mounting)
A bottle of cleaner (I use Windex) and roll of paper towels to clean your plane up after flying.
Glow plug wrench.
The Hobbico combo box you posted is the one I use.
Pre-flight checklist
another list for things to do before going to the field and things to bring (my first trip to the field I forgot my transmitter)