Off the top of my head, here are some additions to your list:-
- Blind filter
- tea towells
- pastry brush
If your espresso machine has a 3 way valve, then a blind filter is a must for doing backflushes, either with or without the Jo Glo.
A tea towell for cleaning around inside the group head, and the sponge for wiping the steam tip.
A bristle pastry brush for cleaning your grinder.
Im sure that theres a few other things, but thats all I can think of now.