The four-cost ramp spell is usually the double land getter Explosive Vegetation and others of that ilk, and that's just 99 cents too, not that bad
Maybe more subtle, but it is definitely there History of the Enchantress deck Enough of that
Birthing Pod Birthing Pod is one of the best creature tutors out there
*Product shown: STARTER DECK -GEAR5- [ST-21]
It's especially popular in The Tenth Doctor decks where it works as a finisher, although it's hard to imagine a card like Worldfire ever being a Commander staple since the unwritten rules of the format discourage mass land destruction
Many frog commanders play in spaces that tie into having lands in your graveyard, whether youre sacrificing them to The Gitrog Monster or milling / surveilling them with Grolnok, the Omnivore or Glarb, Calamity's Augur