This is largely down to Badgermole Cub, which is a clear overperformer in the early days of Avatar
Yuriko, the Tigers Shadow Yuriko, the Tiger's Shadow is among the formats most infamous commanders as its unique commander ninjutsu ability skirts commander tax, making it hard to profitably remove
Or you could let it sit menacingly on your board, wiping your opponent's cards turn after turn
Whispers of the Muse (T1, Ext, S, Block) A favorite in "Turbo Xerox" (a blue deck which used minimal land but a ton of cantrips to thin out the deck), Counter-Phoenix (Shard Phoenix + Forbid) and Tradewind-Awakening (put Awakening on the stack, tap all your lands for mana, untap all your lands), Whispers has what might seem like a hefty price to pay for one card but you get to do it turn after turn after turn
Aside from playing against a bot, all of Magic: The Gathering Arena is PvP, or playing against a real player