80000 hours is a website to help you choose a career that will do good. If you are a student (or if you aren’t a student), I recommend reading their career guide
Robert Wiblin (founder of 80000 hours) put a quick guide to exercise online, suited more to those who want to exercise because they rationally see that they pretty much have to.
I found it pretty useful.
Audacity for editing sound files. This program saved my life in high school music class!
Zotero is an amazing free program for organizing research papers. A must have for any student/researcher. Unlike other solutions, zotero is free to use (for the full version), open source, and comes with free online syncing of your notes. The only catch is you have to pay for online storage, but you can get around that by using an external web service Apparently google drive/dropbox are supported now too!
f.lux is an amazing program that changes your screen colour at night to prevent eye fatigue and make it easier to sleep after using the computer.
Notepad++ for text editing
PDF-XChange Viewer PDF-XChange Viewer is a nice fast PDF viewer that remembers what page you left off on when reading. The free version is good enough to use in my opinion.
Graph is a great free program for plotting functions.
paint.net is a free program like Microsoft paint, but a lot better.