One-off tasks
Within the GTD methodology, it is recommended to have a Next Actions list with all possible next actions (organized by contexts).
One-off tasks are those which can be completed in a single step, in a single sitting. They are not projects by definition as, per David Allen's definition, projects require two steps / tasks:
I do find, however, that one-off tasks can feel a little less important generally than accomplishing a next-action for a project. Therefore, I like to see a distinction within my system (within Todoist).
I'm handling this by adding a one-off
label to those tasks, in addition to the next
label. In this way, they will show up in my Next Actions list, but they will be distinguished by the visibility of that one-off
label in the list.