There are a bunch of icons that still need to be created, but are unlikely to be seen, as they are not on by default. These icons are:

1. delete_table
2. delete_col
3. delete_row
4. insert_col_after
5. insert_row_after
6. insert_col_before
7. insert_row_before
8. table_props
9. cell_props
10. row_props
11. advance_hr
12. select_all
13. absolute
14. abbr
15. acronym
16. cite
17. delete
18. insert
19. fullpage
20. restore_draft
21. spellchecker
22. visualblocks
23. backward
24. forward
25. visualaid

I know these are a lot of icons, and these have all been moved to menus in TinyMCE 4 because they are so hard to represent in a 16x16 greyscale image, but I think if we are going to make the change to these new icons they need to be done properly.