Most of these are for Windows, or are cross-platform (meaning they work on Windows, macOS, and Linux) - but if you're looking for a great list of free, macOS-specific software, check out this one.

Misc Free Software and Utilities

1. Revo Uninstaller - Helps with uninstallation of buggy applications on Windows.
2. Combined Community Codec Pack (CCCP)
3. ImgBurn - Free, full-featured burning software
4. F.Lux - Makes the screen easier to look at after extended periods of time. Apple and Microsoft have both recently built this feature into their operating systems, but this software allows you to have blue-light filters on earlier releases - or, if you wish, more granular control.
5. ShotCut Video Editor - The best free and simple video editor.
6. Freemake Tools - One stop shop for downloading and converting videos from and to any format. Watch out for malware in the installer - uncheck everything!
7. PC Decrapifier - Heard of Microsoft Signature? It's basically just a PC confirmed by Microsoft to have no included junkware. This is the closest thing to automating the process of removing said junkware from your store-bought PC.
8. Defraggler - Best tool for defragmenting that aging harddrive. Have an SSD or Windows 10? You probably don't need this.
9. Speccy - Need to know the specs of that machine? Gotcha covered.
10. MyDefrag - Advanced defragmenting tool with a unique 'defrag on screensaver' option. Not really needed if you have an SSD, or Windows 7 and above.
11. Davinci Resolve is a free(for the standard version), high-end and powerful video editor. It seems they're targeting those who want to stop stealing Adobe's suite or FinalCut, as it really is that powerful. Cross-platform! Free guide.
12. Joy2Key - Great to map keyboard keys to joysticks and controllers/pads.
13. x360ce - Great to do the reverse of the above - make up a virtual controller from any combo of buttons.
14. ColdTurkey - Keeps you productive by blocking the things that aren't.
15. Adobe Flash Uninstaller - Remove a vulnerability.
16. Ardour - Free alternative to FL Studio for audio engineers and musicians. Audacity is a great tool if you need something more simple.
17. Ninite's quick, easy software bulk install tool.
18. KeepassXC - A great, open-source, password manager.
19. AVC Free Software - Free video/audio/DVD converters etc. iOS/Android media managers as well.
20. Tracktion T6 DAW - Free digital audio workstation software.
21. Glass Browser - A simple Picture in Picture (PiP) alternative for Windows and online video content.
22. Peace APO Equalizer - A free equalizer software for Windows.
23. JDownloader- Cross-platform download manager.
24. YouTube-DLG - For video downloading. Fast, and supports more than YouTube.
25. 4K Downloader - Very efficient and simple YouTube video grabber. Feemium, but with few restrictions. I hate to say it, but it seems to work better than the other two open source options at times.
26. TransparentTB - Gives you more theme options for the Windows 10 taskbar.

ProTip: Need to backup your most important documents, automatically? Check out the free or paid versions of Dropbox!

Remote Access

Teamviewer Cross platform!

Chrome Remote Desktop Free, nag-less and crossplatform-ish!

Microsoft QuickAssist - Built in to all x86 Windows 10 devices.

AntiVirus | Security

Third-party antivirus utilities are effectively obsolete.

Instead, install uBlock Origin, stay updated, don't torrent, and use Windows Defender. Backups are important, so use a cloud backup service. Need more protection? Follow this guide.

Alternatively, use CloudReady or get a ChromeOS device rather than a Windows computer. Other Linux variants are an excellent if you're willing to put in the time to learn. Linux Mint Cinnamon or Solus Budgie are a great place to start.

Want EVEN MORE security and privacy? Learn about CoreBoot and Qubes.

1. Norton Removal Tool (SYMNRT)
2. Mcafee Removal Tool (MCPR)
3. Avast! Removal Tool
4. AVG Removal Tool 32-bit / 64-bit
5. Removal Tools for Other Common AV Programs

Online Scanners

1. TrendMicro Housecall
2. ESET Online Scanner

AntiSpyware / Antimalware

1. SuperAntiSpyware
2. SuperAntiSpyware Portable - Just run it!
3. MalwareBytes - Alternate Link

Email | Office | Productivity

1. Mailspring is a fork of the discontinued Nylas/N1 email client. Cross-platform and free for all standard features.
2. Wox - Open Source Windows Search replacement.
3. Microsoft To-Do - Microsoft acquired Wunderlist - this is the result.
4. Sumatra PDF - Read near every type of image-based file.
5. Franz - Pidgin for the modern world. Franz is your messaging app for WhatsApp, Facebook Messenger, Slack, HipChat, Telegram and many many more. Just need Facebook Messenger? Try Caprine.
6. Beeftext - Open Source text expansion, kinda like LH Texter or Phrase Express.
7. eM Client - Outlook alternative.
8. digiKam - Open source photo manager, somewhat like Picasa.
9. RawTherapee - A photographer's tool - an open source photo manager with some oomph.
10. ImageGlass - A simple photo viewer. Want something even simpler, like Picasa's photo viewer? Try nexusimage.
11. Ditto Clipboard Manager - Windows clipboard manager. Must have.
12. WizTree - Find what's taking up space on your computer, faster than WinDirStat.
13. MarkText - A next-gen Markdown editor for Mac, Windows, and Linux. It is a concise text editor, dedicated to improving your editing efficiency. A beautiful and distraction-free way to write.
14. FreeCommander - Total Commander/Windows Explorer alternative for Windows.
15. Listary - This tool makes file-browsing in Windows a breeze for keyboard-players. Allows you to open a prompt anywhere.
16. DeskDrive - Finally, a tool that shows plugged in storage media like Mac OS and Linux DE's.
17. dupeGuru - Get rid of duplicate files. Cross-platform!
18. Windows Live Essentials 2012 - Includes Windows Live Mail, Movie Maker, and so on. Functions in Windows 10(as of January 2018), but you might need to reinstall after every major update. Other things in this list work better than the stuff in Essentials (due to age and compatibility) but I am including for those who need it.

Misc. Resources and Fixes

1. Macrium Reflect Free - Free backup, disk imaging and cloning solution for personal and commercial use.
2. Windows 10 Debloater Script / Windows 10 Reclaimer Script / Windows 10 Initial Setup Script (Enterprise use) - Don't just run these! Read what they do, comment out what you don't want.
3. EasyBCD - Used to modify the Vista/W7 boot configuration database.
4. EASEUS Partition tool - Simple partition manager software. Minitool is also good.
5. Windows XP File Association Fixes
6. Microsoft's own General Help Page
7. Windows Vista / 7 File Association Fixes
8. Windows Update Online
9. LSPFix - repair LSP and winsock - For XP networking issues.
10. Blank Host file - Place into C:\windows\system32\drivers\etc if you can't access websites you used to in Windows 7 and earlier.
11. MSKB: Messages stuck in Win Mail - Howto fix for a common problem on Windows Vista.
12. Reset Registry Permissions - Used to fix "Access Denied" errors installing Service Packs and updates (XP only). Extract, run MSI file, then run CMD file. If window opens then closes right away, copy to and run from C:\Program Files\Windows Resource Kit\Tools
13. RunOnce Remover - Removes the "Welcome to IE7" on first run
14. IE6 Reset Tool - Resets IE6 somewhat like hitting "Reset" in IE7
15. Windows XP Installer Fix - Resets and re-registers Windows Installer components (WinXP/2k 32-bit only)
16. Windows XP Installer Reinstaller - Removes all versions of Windows Installer, restarts, and starts install of Installer 4.5 (WinXP SP2+)
17. Group Policy Installer/Repair for XP Home/Pro
18. DriverMax - Copy drivers from one machine to another.
19. Kelly's Korner - XP Registry fixes
20. Microsoft FixIt Center - Diagnoses common issues and offers solutions.
21. Fast Fix For "Admin set policies to prevent this installation" Error - Win XP Only
22. Alternative Fix "Admin set policies to prevent this installation" Error - Win XP Only
23. Print Spooler Reset Tool - Run, choose "Light Mode" to just reset spooler, choose "Full Mode" to reset everything relating to printers, *Will need to reinstall all printers afterwords*
24. Enable Task Manager - Download and run
25. Show all Hidden/Nonpresent Devices
26. Fix add/remove administrative error
27. Autoplay Repair Tool
28. Upper/Lower Filter Fix - If your CD/DVD drive won't work in Windows inexplicably, try this.
29. CompactGUI - Shrink application file sizes in Windows.
30. Legacy ASIO Behringer USB driver - Better than the newer stuff. 32-bit / 64-bit
31. EasyCAP drivers for Windows 8, 8.1 and 10
32. BIOS password revealer for Dell Latitudes
33. Copy iPhone text messages to PC