Favourite tools or programs on windows

there is some programs that are kinda very useful
i'm talking about programs that are just very small in size but can do alot of stuff
for an example i will start:
Ultraiso: with all it's awesome features and simplicity and easy interface
winrar: easy,simple,fast,mutli functionals
winampnly around ~20MB and can be better than huge in size music players plus it's fast,easy to use,lite
K-Lite Codec: small in size,easy to use,adds codecs to whole windows so that windows media player can run all extensions plus allowing games like GTA to work fine
7zip: sure everyone knows what is it capable of

i know there is other programs out there that are small in size and can do magic that's why i'm asking

for an example of these magic tools is Selfishnet :less than 1mb ,works like netcut,ability to see who is using your connection, limit their upload and download speed (unfortunately the program is out of development but still works with some bugs)

and there is much more i know and i don't know
i know that some info like these are actually worth alot of time to discover and so most of the people know these stuff don't tell
as Lao Tzu said "he who knows, doesn't speak.he who speaks, doesn't know''

i speak, that makes me don't know and that's why i'm asking

so why not share with us some of your must try or have tools and programs
and have a nice day