The Portable Freeware Collection Forums

https://codedead.com/software All are free, several have a portable version, some have a Softpedia entry, some are open source
https://www.horstmuc.de/index.html
http://www.joeware.net/freetools/index.htm
https://www.donationcoder.com/
https://elefantsoftware-en.weebly.com/download.html All free many (maybe all) portable

https://www.carifred.com/ "Carifred - IT software for Windows"
Several tools are freeware, ... others are payware.
Most of these tools are oriented toward system rescue, security, Windows system administration.
Some of these tools have a Softpedia page.

https://www.mediahuman.com/products7.html
(Download page: https://www.mediahuman.com/download3.html )
Mostly utilities for finding and processing multimedia content on the web.

https://luethje.eu/prog/ Freeware
Utilities for working with accented characters and related tools
Most tools are portable (zip files)

Freeware developed by Jochanan Agam: https://freeware.persoft.ch/freeware_en.htm

List and download links: https://freeware.persoft.ch/program_en.htm

https://www.willus.com/archive/

From the web site: Willus.com's Software Archive
These programs are all freeware.
Win32 programs run under Windows 95/98/Me/NT/2000/XP/Vista/Win7.
Win64 programs run under Windows Vista/Win7 64-bit.
Some programs require DOSBox to run under Win64 (Windows Vista/Win7 64-bit).

Applications with GUI and/or Command Line

Categories:
Photo Processing
Math, Science,Plotting
Games, Educational

https://www.rathlev-home.de/home-e.html

The web page was last updated January 14, 2024

Among the applications that may be very useful (I did not test them):

R-Plot - Visualization of measuring data
R-Plot is a Windows program for presenting measuring data as X-Y diagrams, bar charts or histograms. Optionally you can add error bars, best-fit curves, computed functions, images, text and simple graphic objects. The number of charts per sheet and objects per chart are in theory unlimited.

BibTeX Editor
WinBib is a program for editing and managing BibTeX files. It supports all entry types defined in BibTex, but is especially designed to manage the article type that is most used.

Integrated Development Environment for 8051 Microcontrollers:
https://www.rathlev-home.de/mc/mctools-e.html