Can planeswalkers use their +1 abilities even if it would have no effect? For example, could I use {Lilliana Vess}'s +1 even if my opponent has no cards in their hand?
Yes
Sweet, thanks. Me and a friend of mine got in an argument about that
What about Ral Zarek's +1? Lets say no creatures are on the battlefield at all (so you can't tap nor untap anything). Still get the +1?
{Ral Zarek}
For his ability you must have two permanents to work his +1 since it says target permanent. The target must be valid to work.
In liliana's case, the valid target is the player, and since the ability does not check the number of cards, it works. However if discarding is part of a cost, and that you do not have a card, then you cannot activate the ability, say {Amok}.
Quote from: EstimatdProphet on July 10, 2013, 05:23:28 AM
What about Ral Zarek's +1? Lets say no creatures are on the battlefield at all (so you can't tap nor untap anything). Still get the +1?
Ral's +1 says "permanent," not "creature." That means anything on the field - creatures, lands, artifacts, even enchantments and planeswalkers if you want.