If you want to go big, cards like Doubling Season, Vorel of the Hull Clade, Winding Constrictor, and Deepglow Skate can double or even explode the number of counters, making your payoff cards hit game-ending levels in just a turn or two
From the Generation Force set
2 Team Rockets Moltres ex (Special Art Rare) $89.90 Moltres adds another card to some of its most valuable, as this amazingly valuable Glory Of Team Rocket chase card blows its competitors, save for one, out of the water

Aang, Master of Elements Aatchik, Emerald Radian Acererak the Archlich Aclazotz, Deepest Betrayal Acolyte of Aclazotz Adeline, Resplendent Cathar Adeline, Resplendent Cathar Adriana, Captain of the Guard Advanced Reconstruction Aether Syphon Agate Instigator Age of Ultron Agent of Masks Agent of the Fates Agent of the Iron Throne Ainok Strike Leader Ajani, Nacatl Avenger Akroan Horse Aku Djinn Akuta, Born of Ash Alchemist's Talent Alhammarret, High Arbiter Altar of the Brood Amphin Mutineer Anax and Cymede & Kynaios and Tiro (playtest) Angel of Indemnity Angelic Arbiter Angrath, the Flame-Chained Angry Rabble Anje, Maid of Dishonor Anya, Merciless Angel Arabella, Abandoned Doll Araumi of the Dead Tide Arbaaz Mir Arbiter of Woe Archers' Parapet Archfiend of Despair Aria of Flame Ark of Hunger Armor Wars Arrogant Outlaw Arterial Alchemy Arterial Flow Ashiok's Adept Ashiok, Nightmare Muse Ashling, Flame Dancer Aspiring Champion Astral Confrontation Atarka's Command Aurora of Emrakul Auton Soldier Avacyn, the Purifier Avatar of Growth Avengers: Under Siege Awaken the Blood Avatar Ayara, First of Locthwain Azor, the Lawbringer Baba Lysaga, Night Witch Bad Deal Baleful Beholder Balemurk Leech Bandit's Talent Baneful Omen Banshee of the Dread Choir Barrensteppe Siege Basilica Bell-Haunt Basilica Guards Basilica Screecher Bastion of Remembrance Battlefield Butcher Belonging Benthic Anomaly

In case youre unaware, one of my very first Commander decks was a Lyra Dawnbringer deck which eventually evolved into my Giada, Font of Hope deck
Rapid Strike Energy Rapid Strike Energy serves as a pseudo Twin Energy or pseudo Double Rainbow Energy for any Rapid Strike Pokmon, making them easier to get powered-up and attacking early