Taunt is the better choice over Heal Block, since the most common healing moves are non-damaging, exceptions being Horn Leech, Giga Drain, Oblivion Wing etc. Taunt is pretty much the best and only option I can think of, as it prevents non-damaging healing moves but also all non-damaging moves.
Taunt has a relatively wide distribution, as seen here. Best user is Prankster Sableye due to its immunities and access to Will-O-Wisp to stall physical sweepers. Other good users include Prankster Whimsicott, Crobat and Froslass.