(also, the quick key for un-minimized is shift+windowskey+m)
Always on Top
Eyedropper (dead, archive.org link)
Newest version may have memory leak issue (slows down the more you use).
Apparently autohotkey also has a similar function in their "window spy" feature. Not very visual, but maybe more stable.
Eye dropper with this Optical Illusion
Text Mining Tool
Windows Grep (also has Search and Replace)
File menu tools
I should have also mentioned this ISO producer that's been around for a long time. Super tiny file size
Recommended by Users
This is supposed to be a list of tiny (small file size) freeware not many people know about. Please don't ask why I didn't include gimp, open office, audacity, camstudio, virtualdub or other random programs I've already talked about.