All of those work a ton better when you're at around 38 lands
Say you want to pick up some foils and cards with altered art
Then, when Keruga enters the battlefield, draw a card for each other permanent you control with a mana value of three or greater, which will be all of them
[48] [49] [18] Black represents power, death, corruption, and sacrifice, drawing mana from swamps
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)
Then play returns to the Main Phase, where the current player can perform further actions until they cannot, or do not want to, perform any more