textobj-indblock (GitHub: glts / vim-textobj-indblock) is a set of text objects for selecting whitespace based on the current line's indentation. It supports Visual and Operator-pending modes, and it built with textobj-user by Kana Natsuno.
qfnotes (GitHub: khorser / vim-qfnotes) by Sergey Khorev allows files to be annotated using a quickfix window. With a file open, pressing
\qn displays a prompt for a note, and then notes can be loaded later with
:QFXLoad. If search or compiler output overwrites your notes, then
:colder will refresh them.