Ubuntu list
For Ubuntu, I find these invaluable:
* Grub-customizer -- published via Daniel Richter's PPA. Graphical set-up of GRUB entries, allowing you to edit the stanza titles, hide unwanted boot stanzas, change the ordering of stanzas, group in sub-menus, change the splash screen size, etc. Excellent tool.
* nautilus-open-terminal -- Nautilus extender to open a terminal in the given folder.
* Byobu -- 'screen' on steroids. Look up either 'byobu' or 'screen' if you don't know what these "super shell" tools are.
* gprename -- group file renamer.
* FWKNOP -- Super-secure firewall knock operator, using SPA to open a given port for an originator at a given IP number. I use it to unstealth SSH ports for entry.
* testdisk -- reconstruct deleted/overwritten/lost/damaged partitions. A lifesaver...
