Dogmeat, Ever Loyal Interceptor, Shadow's Hound Isamaru, Hound of Konda K-9, Mark I Karvanista, Loyal Lupari Kroxa and Kunoros Kunoros, Hound of Athreos Lockjaw, Slobbering Teleporter Lucky the Pizza Dog Mowu, Loyal Companion Pako, Arcane Retriever Phelia, Exuberant Shepherd Rex, Cyber-Hound Rin and Seri, Inseparable Tesak, Judith's Hellhound Yoshimaru, Ever Faithful
Value or combo, you choose your own route
So, essentially, extra turn spells have a rate (in the modern era) of costing a variable five mana, a la Time Warp
While Mardu Humans wouldn't win every game in the precon-vs.-precon meta, I think that its combination of being fast, efficient, and consistent would give it a leg up on the rest of the field over a sample size of several to many matches
This can mean that its spelled wrong, youre trying to pull the card from a set that it isnt in, or the collector number is incorrect or not formatted properly
And dont worry about discarding cards to reach the card advantage