I would like to recommend several apps. To make things easier for you, you can download them at once from this WeTrans-link: https://wetransfer.com/downloads/26e0594170e5521d4a89372a72a15b4f2018010... After download, you have two ZIP-files. The large one (about 350 Mb) is encrypted with the password: PortableAppsDotCom. That one contains all the software. The other one contains shortcuts. When you unzip the software-package at the root of the C-partition, then everything wil appear in a folder called "Program Files Portable (x86)" Then you should be able to access them with the shortcuts. The shortcuts also are linked to readme-files, manuals and external website-links.
Here is a description of the software:
ocenaudio ( https://www.ocenaudio.com ) : Probably allready familiar by you. The best thing is it supports many audio-files and can export many files at once. I use this mainly to split for example a large flac-file by a cue-sheet. ocenaudio supports a lot of audio-files. On the other hand, it works for me personal less practical then I first assumed. The Zoom-function really confuses me and there ain't a help-file or guide. It's very personal if someone likes this software.
You allready include WaveShop in your app-library. A very basic audio-editor, however it is interesting because of the 'bit-perfect'-editing. The developer Chris Korda has many more free tools and some are very interesting, like Mixere ( https://sourceforge.net/p/mixere/wiki/Home ), TripLight ( https://sourceforge.net/projects/triplight ) , Fractice ( http://fractice.sourceforge.net ) and World ( http://whorld.org ) . You really should check it out. Mixere and TripLight can be downloaded as portable software. Unfortunately the other ones which are really interesting require a setup-procedure. I dunno you can make it portable.
Wavosaur ( https://www.wavosaur.com ) : also an audio editor with some very handy extra functions
Musette ( https://musettemusic.com ) is music notation software. If offers less functions and intuitivity than for example MuseScore. On the other hand - it is very lightweight and all program files together take some 10 Mb, which is 15 times smaller than MuseScore
G3C ( http://g3c.software.informer.com ) : a small piece of software which offers tuning and practice for guitar playing
Virtual Piano: also very small and lightweight. I use it mainly to check in which key some tone is. Because it starts up very fast it works practical for me.
There are many free tools for music creation. However it's hard to find decent tool specifically for MIDI-editing. However Temper ( http://www.angryredplanet.com/temper/ ) looks very promising. I haven't worked with it, but it looks very promising. Another option is Jazz ++ ( http://jazzplusplus.sourceforge.net ) . Also Aria Maestosa ( http://ariamaestosa.sourceforge.net ) can be an option, however I find this software quite buggy and it offers less options for MIDI-editing. On the other hand Area Maestosa is very intuitive and the structure of the software is quite interesting.
People who compose music on the computer frequently use SFZ-files or SF2-files. Polyphone ( http://polyphone-soundfonts.com/en/ ) is a free and easy to use soundfont-editor which also can import a lot of SFZ-files. (Other free interesting software is Ploque SforZando ( https://www.plogue.com/products/sforzando/ ) , however I suspect it cannot be made as a portable device.)
pxTone ( http://www.cavestory.org/pixels-works/pxtone-collage.php ) is a free software package containing several applications especially designed for creating 8bit or 16bit retro game music. The software is popular by people who compose music for free games, because the files can be integrated into the games. Those files are like MIDI-files - they just contain commandos to instruct which sounds must be generated. Unlike MIDI it sounds the same on any computer. The reason why I find pxTone so interesting is because you can do a lot more with it than just creaty bleepy game music. pxTone offers a tool to create sound FX; it works very intuitively and when you have a bit of basic knowledge about synths you can easily experiment with it. Also when you use more 'serious' software like Cakewalk Sonar pxTone can be very usefull for inspiration. (the sounds and soundtrack of this free game are created with pxTone: https://youtu.be/pwDf8zSCD1M The composer who made this has also written a very clear user manual.)
VidCoder ( http://vidcoder.net ) is an adepted version of HandBrake which works more stable and is also easier to use.
Light Alloy ( http://light-alloy.verona.im ) is a free lightweight media player. Like VLC Media Player it can run many codecs on its own. It is also translated into many languages.
Pazera ( http://www.pazera-software.com/products/audio-extractor/ ) offers several free tools to convert any kind of media-file into another. The most interesting one for me is the Free Audio Extractor.
For authoring DVDs you include DVDStyler. It really is interesting software, however in practice I encounter problems with playback on DVD-players. When reading about it that probably has to do because the way the videos and menus are authorized. On the website Videohelp.com I found several tools including DVDAuthorGUI ( https://www.videohelp.com/software/DVDAuthorgui ) . It looks more outdated and it doesn't include video convertion. However it seems this can produce better authorized video DVD's.
For video convertion to MPEG2 DVD there's HC Encoder ( https://www.videohelp.com/software/HC ) . It is quite difficult to use (there are tutorials), however it can encode just as good as TMPEGEncoder. You can set everything manually.
DVDSubEdit ( https://www.videohelp.com/software/DVDSubEdit ) is a very handy tool for extracting and edit subtitles.
Xiberpix Sqirlz ( http://www.xiberpix.net ) offers three morphing editing tools: Face morphing, Morphing and animating and water reflection animations. On the website you can download them as setup-installers, however the software can run portable as well.
Tile Studio ( http://tilestudio.sourceforge.net ) is graphic software for creating pixelart or sprites for games.
VirtualDub FilterMod ( https://sourceforge.net/projects/vdfiltermod/ ) is an adapted version of VirtualDub. The best thing about it is it supports reading a lot of codecs on its own, so you don't need to install external codec packages to work with VirtualDub. This also makes it more portable. VirtualDub also comes with a 64bit version (not included in my download), however that doesn't support the main external filters. Speaking about filters .... you can download a so-called Filter-package containing more than 200 plugins. All those plugins will show up in the filter library, which makes it very chaotic and unorganised. I spent time and effort to find out which filters are usefull. I even found more very cool filters which are not included in the filter package (Kagayaki filter).
Some other tools I can recommend:
Erunt: software for creating back-up of the Windows Registry
RKill: This ain't a mallware or other harmfull software remover, however it is essential when you need to scan and delete mallware, trojan horses, virusses, etc. It kills them for being executive ... only then software like Mallwarebytes or SUPERantiSpyware can remove it.