I've been building some new raised beds this year so I am big on finding new sources of soil building materials.

I use all the sources you mention except the coffee grounds - there aren't any coffee shops nearby.

I've got a big 100ft+ tall sycamore tree in front of the house. That is providing me with a lot of leaves. I have wondered how many kg of leaves such a tree provides. Maybe I should weigh them somehow as I collect them...