How do you locate software?

I have a project to replace an out-of-date software product we use with something else. I’m having trouble locating alternative applications. Obviously I could order the newest version of the same app from the vendor, but I’d like to see other programs that do the same thing.

How do you locate an application when you’re looking for one? Yeah, I know you go to <>, but I’m having trouble separating the wheat from the cyberchaff. I have a list of required features, but I don’t know how to pre-screen apps so I don’t have to download and run them one at a time.

For those who want the gory details, the existing app is eCopy Desktop 7.1. We use it as a print driver to build .TIF ECO files from various original file formats and scanned images. We use it’s Markup tool to indicate changes to originals, and it’s Stamps tool to insert signatures and ‘Approved’ graphics. We also use it’s integration with Outlook to forward the assembled / approved ECO in a rudimentary workflow system. We could upgrade it at $200 per user. I’ve tried MS Office Document Imaging but the Markup tools lack several capabilities we have in eCopy (no arrows, no boxes or rectangles, only free-form drawing, etc.) I looked at MS OneNote since I had a copy but discarded it as totally unsuited.