In this Adobe After Effects example, animated lines form the rough outlines of letters, which are in turn filled by a Scribble effect
Firstly I created a text layer as a reference (the font used was Gotham Bold), which I then traced by hand using the Pen Tool, editing points as needed, but also with some artist licence in over shooting some lines.

To each of these strokes was added a Trim Paths. Once I animated one path to my satisfaction using the Graph Editor, I copy and pasted those keyframes onto the other Trim Path Start and Ends. 

I then duplicated my text reference layer, and converted the text to masks. To this the Scribble Effect could be applied. The keyframes for the start and end of the Scribble Effect were made in reference to using the outline stroke animations for timing.

To make the composition more adaptable, the colour and size of the outline strokes were all controlled by a Controller Null layer with Expression controls - a colour picker and a slider control. A separate Controller Null was made for the scribble colour.

Once pre-composed, this was brought into the main composition and made into a 3d layer, with added camera and a Camera control Null. This was animated in 3D space, with a Glow effect added and some light particles