Gev helps keep the pressure on opponents with several abilities that support aggressive playstyles, and it's also a rare typing, with both Lizards and Mercenaries among the rarest subtypes in Magic: The Gathering (at least prior to the last few sets)
It brings the creature back to your hand, so itll be useful if youre reusing something with a good enters ability
Silvar becomes that sacrifice outlet with Zulaport Cuthroat and Bastion of Remembrance that will help you put the finishing touches on your opponents
Slayer meanwhile has exactly three great picks to send, only needing to account for Fusions, Synchros, and Xyz
Then you can spend a mana to keep it from being blocked by anything without the "haste" keyword evasive and a faster clock with haste to draw another card a turn earlier
Insolent Neonate 2 Not really what you are after in this deck but sometimes a suitable patch over card