PDFsam Basic, Windows, free (merge, split, and rotate PDFs)
https://pdfsam.org/

PDF Toolkit+, macOS, $1.99 (merge, split, and compress PDFs)
https://itunes.apple.com/us/app/pdf-toolkit-+/id545164971

Nitro Pro, Windows, $160 ($20 for members of Washington University)
https://www.gonitro.com/

SoftMaker FreePDF, Windows, free (limited PDF editing)
https://www.getfreepdf.com

Qoppa PDF Studio Pro, Windows, macOS, and Linux, $90 for Standard, $130 for Pro
https://www.qoppa.com/pdfstudio/

CutePDF Writer, Windows, free (print to PDF)
https://www.cutepdf.com/Products/CutePDF/writer.asp

CutePDF Professional, Windows, $50
http://www.cutepdf.com/products/cutepdf/pro.asp

Foxit PhantomPDF, Windows and macOS, $130 for Standard, $160 for Pro (Windows, only).
Or just $10/year for anyone with an .edu email address.
https://www.foxitsoftware.com/pdf-editor/

Classic PDF Editor, Windows, $25
http://www.classicpdf.com/

Infix PDF Editor, Windows and macOS, $100
http://www.iceni.com/