Low Fidelity Prototypes include:
Sketching – is a free-hand depiction of images related to the final design.
Storyboards – are common way to provide a narrative putting the design into context. It provides an opportunity to see how the user will engage with a given scenario. The below storyboard is from RuoCheng.me.
Card-Based prototype – allows us to see at the sequence of iterations the user might have with the designed interface.
Usability.com/Prototyping – includes an excellent graph by Tracy Lepore visually showing the evolution from sketch to design.
Lo-Fi vs. Hi-Fi Prototyping: how real does the real thing have to be? by Florian N. Egger on telenovo.com.
High-Fidelity vs. Low-Fidelity prototyping in Web Design and App Development – by Kim Doleatto on http://www.atlargeinc.com/
UX Recorder – Good for mobile user testing on iOS
Invision – Free design prototyping tool
Marvel App – Free version – prototyping tool for all type of devices.
Azure – the most used software.