EagleFiler is described as 'makes managing your information easy. It lets you archive and search mail, Web pages, PDF files, word processing documents, images, and more. Use it to collect information from a variety of sources. Browse different types of files using a standard three-pane interface' and is an app in the File Management category. There are more than 50 alternatives to EagleFiler for a variety of platforms, including Windows, Online / Web-based, Android, iPhone and Mac. The best alternative is Joplin, which is both free and Open Source. Other great apps like EagleFiler are Standard Notes (Freemium, Open Source), Microsoft OneNote (Freemium), Evernote (Freemium) and CherryTree (Free, Open Source).
Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, can be copied, tagged and modified either from the applications directly or from your own text editor.