Updated my old ai_viewanimations.lua re-write to use my utillib and somewhat improved it all round really.
Just attach it to one or more animated entities then you can walk around testing out their animations.
Instructions appear on screen but I'll recap here in more detail:
LMB to increment the frame, RMB to decrement
Press Shift to increment/decrement quickly
E to change 'from' frame to 'to' frame or back again
Shift+E to toggle looping animation
Script automatically detects which entity you are looking at (have to be within 200 units of an entity to control it but that is easy to change in the script if need be).
Edited: Forgot to mention that I renamed it so it doesn't clash with the one already provided with GG.
Been there, done that, got all the T-Shirts!