Top Alternatives to Osmo

Evernote is a note taking application which keeps the notes taken in sync across all platforms using its cloud infrastructure.

Notezilla is a sticky notes app for Windows.

Joplin is an open-source free note taking and to-do application.

Lightning App Builder is a point-and-click tool that makes it easy to create custom pages for Salesforce1 and Lightning Experience.

wikidPad different from other notepad applications is the ease with which you can cross-link your information.

CherryTree is an hierarchical note taking application, featuring rich text and syntax highlighting, storing data in a single xml or sqlite file.

Rainlendar is a calendar program for Windows, Mac OS X and Linux.

NixNote is an open source client for Evernote.

ResophNotes is a fast note writing tool and a Simplenote client on Windows.

BasKet Note Pads is a KDE program for organizing, sharing, and taking notes.

WizNote is a cross-platform cloud based note-taking client.

Leanote is a self-hosted note taking app.

Zoho Notebook takes the same catch-all approach as Evernote and OneNote, but has a few design ideas of its own.

Guide is an application that allows you create documents ("guides") which inherently have a tree (which you can modify as you please) and text associated with each node of the tree.

BeeCanvas is an online whiteboard based visual collaboration tool.

footnote is a very light and neat Notebook App for elementary OS.