I’m not looking for a full PDF editor. Only to do tasks like merging and splitting PDFs, removing pages, or creating a PDF from a bunch of images.
https://www.ilovepdf.com is very handy, but I don’t like the idea of uploading my documents to them, especially if they have sensitive data.
I use command line tools for this, for most those things pdftk should be enough and it works great -if the command line is too daunting for you, there’s PDF chain a graphical front-end for pdftk.
For creating PDFs from images i often use imagemagick.