{plaugemaw beast}
Is the loyalty of planeswalkers considered counters, and can you use PB to add another to it?
You betcha!
Planeswalker do indeed have loyalty counters to track their loyalty. And planeswalkers are permanents, so they are valid choices for proliferate! Have at it!
Wow...I gotta ditch that stupid {the chain veil} and get more of those! Thanks!