Well, Daminion seems a good attempt at what I want as a image organizer - I'm not saying it's the best because it's not, but I'll keep it to see how it develops - however it's a bit slow and sometimes takes a while to redraw thumbnails. One thing I like about it is the smallish db size and it not being java-based, also I very much like the ergonomic layout.
I've tried :
exifpro - don't like the layout
IDimager (not free)
and a few others which I won't mention as I find them lamentable. At the moment I'm testing :
Cloudatag which (although it comes from beyond the silk curtain) seems pretty good as a simple tagger and organizer, very fast and apparently stable but of course I don't use the remote cloud option,
and StudioLine PhotoBasic which is more powerful but looks promising.
As for your last question : "other document types...", I use Tag2Find (no longer developed) which is great for my vast collection of letters and docs but not for images as it does not integrate a viewer.
Thanks for your curiosity ...