We can do this three ways: first, there's cards that specifically allow extra activations, like The Chain Veil
Nature's Lore Nature's Lore is an extremely popular green card in Commander, simply due to its efficiency and cheap cost
Najeela, the Blade-Blossom or Urza, Lord High Artificer and deny your opponents the ability to activate their own
(2018-07-13) If a replacement effect allows a player to modify or replace an event by putting counters on a creature or player affected by Suncleanser, that player may apply that replacement effect, but they wont get counters
That alone would make this on my Top Ten list and make it worth the 7-mana investment
You can't play an 8 drop in a normal deck and have much chance of it doing anything