Although I have never understood why it's called rsync, because you need to add --recursive to make it actually sync a file tree, which is what it does best.
xournal for fake form-filling on PDFs - ugly and unintuitive but gets the job done
img2pdf - does what it says on the tin
ranger for managing files and launching stuff - not the coolest kid on the block but this is the single most impressive terminal app I have used in recent years, the key bindings and commands and defaults are so crazily intuitive that I hardly ever even need to consult the manual
Very similar to you. I do use gramma for spellchecking. My most used app overall is probably pandoc. I use it to make all my docs and presentations for work.
pdfcrop (commonly included with LaTeX) for cropping margins - it cuts the pdf down to its contents then adds a margin of your choosing, extremely useful for forcing academic papers to have consistent margins, pdfcrop --margins 72 *pdf here* will create a document with a ~1in margin all around (it uses bp as its units)
vips for resizing/converting images - it's a bit faster and lighter than imagemagick in my experience, although the main reason I use it instead of imagemagick is just because I like playing around with stuff I haven't used before :) It has an officially supported python binding too
I use most of these that you listed, except that I don't use office apps at all, and do all my documents using LaTeX in neovim.
Also, I have small helper scrips for pdf manipulation for tasks that I do regularly, like making my handwritten notes ready for printing at my office since I don't like the algo my office printer uses to convert them to B&W. I also use sejda-console for merging PDFs as it has nice options for manipulating TOC during the merge.
Another nice utility is ffpb which is basically a wrapper around ffmpeg that gives it a nice progress bar.
For me, it's pretty much just app management via my package manager, some file management, and the big ones are using neovim as a text editor and cmus as my primary music player (I also use emms in emacs sometimes)
@antihero I use ffmpeg to extract frames from images. Yt-dlp to download youtube videos. Rmlint, to remove duplicates. Gallery-dl to sometimes download from sites like instagram or twitter & finally mpd / ncmpcpp to listen to music....
convert - convert between image formats as well as resize an image, blur, crop, despeckle, dither, draw on, flip, join, re-sample, etc. Almost nothing it can't do.