I have writtem for my own use, a program inspired by the old Windows
cardfile,exe. It can file text, tabular and image cards.
All can be created by pasting from the clipboard and all can be reading
files: .txt, .csv and various image formats such as .jpg & .png. Any
individual card can also be saved to a file of appropriate format. It
doesn't support mixed type of data on a single card but cards of
different types can be mixed freely.
Text and tabular cards can also be created blank for manual data entry.
The saved format for a collection of files is text, any images being
saved in base64. A saved file can be merged into the current file.
An extension also attempts to simplify entering text from PDFs with an
OCR layer. These notoriously have lines of original texxt fragments.
This will simply join t paragraph's worth of fragments back into a
single paragraph - it won't deal with misread characters or fragments
which hav got out of order.
It's developed in Lazarus/Free Pascal. Although it's developed on Linux
Lazarus is available for Windows & Macs as well.