Hex Maniac is a Supporter that nullifies or "turns off" Pokémon Abilities from the moment played through the end of his/her opponent's turn. All Pokémon whether in play, in hands and both discard piles are affected. Example: player A whose active Pokémon is an Yveltal EX can not normally inflict damage from its attack onto a defending Carbink because of Carbink's Safeguard Ability. However, should player A play a Hex Maniac, player A can then attack and inflict damage onto the defending Carbink.
Pokémon Ranger is another Supporter that also momentarily turns off a "lingering" (i.e., extends beyond the current player's (initiator) turn) effect a player A may have imposed upon player B. Example: player A, using Giratina EX's Chaos Wheel attack, inflicts damage as well as imposes an effect onto player B preventing player B from attaching Special energy and Tools and placing Stadiums on player B's next turn. However, should player B play a Pokémon Ranger, the Chaos Wheel attack's effect is terminated immediately and player B can attach Special energy and Tools and place a Stadium. Note that if player A attack's effect had placed damage counters, this effect is not lingering, but immediate and done. So, player B, playing a Pokémon Ranger, could not undo the previous player A turn's damage counter placements. It is also my understanding that Pokémon Ranger will not undo Special Conditions imposed by player A on his/her previous turn.
Lastly, should you have any concerns, especially during any upcoming tournament, I'd suggest you consult with the head before the tournament starts and even during the tournament, if need be. Also note that some official rulings may not always be current when new cards are released; so, some "local" rulings may apply.
Hope this helps.