Long story short Ragavan is a house against any deck, is pure mana acceleration and card advantage, and packs them both together in a body that should cost way, way more than one mana
Some Planeswalkers have the text [planeswalker name] can be your commander written at the bottom
And yes, I can hear the counterargument that people should play answers to problem permanents in their Commander decks, and that is certainly true, but heres the thing: sometimes in 100 card decks your answers dont come up
Geological Appraiser feels like a slightly watered down, but Standard legal, Bloodbraid Elf
Kiki-Jiki, Mirror Breaker, Splinter Twin, and Orthion, Hero of Lavabrink make token copies of a creature that dies in the end step
Many of your creatures become more valuable the longer they remain in play, so be cognizant of when to trade them off in combat and when they'll be big enough to dominate the board in a turn or two