Welcome to TVPaint Community forums !

i have a question, is it possible to, without messing with pressure's profile editor
can lines be switching between sizes randomly while drawing?

(Obviously there has to be a limit size for a range of the sizes to work under eg: 3.00 then all the sizes will randomly switch between (0.50-3.00))

You could do an animbrush (a custom brush with animation).

Where is that located?

in the tutorial section :

Hey, thanks again! really appreciate it ^ ^