This has been entered in the bug tracker with slight differences. See #19 in this thread.
I think first, you need to decide how you want to represent various forms of link/file (unchecked, available, not found, unavailable, duplicate, downloading, downloaded, and completed) and the same for a package.
Is a package a folder? Nobody has a trademark on a drawing of a 1/3 cut file folder. The same for use of a ladder as an archive. Circles, arrows, disks, and check-marks are also generic. None of this has a specific source.
If you limit to three primary foreground colors (blue=neutral, green=good, Orange=trouble), you avoid color blindness problems (each must be a different brightness)
.
Circle means open middle. Disk means solid.
Once the icons are chosen for states of items,
then a pair of scissors can represent deletion.
The space for icons in the table is 16 pixels high.
The Action icons can be 32 pixels, so there should be space.
Code:
Link/File Package Archive Unit
unchecked Blue
Circle N/A N/A
available Green Green Green
Circle Circle Ladder
not found Orange Orange Orange
Circle Circle Ladder
temporarilly Blue N/A N/A
unavailable Disk
exact Orange N/A N/A
duplicate Disk
mirror Blue N/A N/A
downloading Hand Mirror
mirror Orange N/A N/A
redundant Hand Mirror
downloading Green Green arrow Green arrow
Down Arrow on Folder on Ladder
download Blue Blue arrow Blue arrow
temp. failure Down Arrow on Folder on Ladder
download Orange
perm. failure Down Arrow on Folder on Ladder
downloaded Blue
Check Mark on Folder on Ladder
completed Green
Check Mark on Folder on Ladder
If you like the ideas and the parallelism, then let me know.
I can draw these for you in Photoshop. I would draw them 128x128 and then resize as appropriate (the reduction creates some anti-aliasing that makes it look nicer). The originals would be PSD to preserve layers (such as for adding scissors, hands, usw.).
Saving as PNG would be no problem.