Forbidden Orchard straight-up gives an opponent a 1/1 creature. A creature with a strong tribal type no less. Is one mana worth giving your opponent another body? As someone who's died to a 1/2 Hunted Ghoul, I have my doubts. Those who've never suffered that fate may disagree.
Finally, I don't know how to classify Gemstone Caverns. It's one half leyline, one half Gemstone Mine. Sometimes it creates mana of every color. Sometimes it doesn't. It's not a cost exactly, though you are putting it into your deck instead of an on-color land. It's not a condition exactly, but it does only work if you have it in your opening hand.
Meteor Crater could add mana of any color to your mana pool, but it usually doesn't. It's limited to creating mana that shares a color with a permanent you control. It's the first of a series of lands that experiment with different restrictions on the colors of mana they produce. Meteor Crater doesn't seem to do a lot of good; if you already have the color to play that permanent, do you need more of it? When Meteor Crater came into play, there weren't hybrid cards, so maybe it's a little more versatile now.
Exotic Orchard is another "limited potential" card, instead reigning itself in according to what your opponents' lands can produce. It was released in Alara, where players were encouraged to play three or more colors. In that environment, it was likely to get at least one mana of a color you needed out of it, interacting with your opponent's deck without really harming them.
Exotic Orchard is also interesting because it's obviously based on Fellwar Stone, a two mana artifact that has the exact same ability. Though Exotic Orchard doesn't cost anything to play, Fellwar Stone is a lot more popular. I think the reason for that is that the Orchard gives you the exact same functionality, but forces you to use a land drop to play it. On the other hand, the artifact gives you "bonus" mana above your land drops. If you're lucky, it might be a color you need.
The different expectations that players have for lands and artifacts is a key factor in how successful they are, not in the metric of "games won," but in that of "players excited." It's that second one that's going to keep Magic alive in the long term.
Command Tower is, I think, the last "limited potential" land. While Exotic Orchard is well-liked in multiplayer, Command Tower is literally made for it. Because of the restrictions of the Commander Format, Command Tower essentially adds one mana of any color you need to your mana pool. It's a card which uses the restrictions of its format to balance it and that's pretty nifty.
As an aside, I like the card, I want it in every Commander deck I have, and every player wants one in every Commander deck they have. I don't know if that makes it a good card or not. Auto-include cards don't strike me as being particularly compatible with the spirit of deck customizing games. As much as I might like it, I don't think it's a particularly good card.
How You Spend It, aka Questionable Charity Spells
There are also lands that provide you with any color of mana, but limit what you can use it on. Primal Beyond was made to support the five color elemental tribal theme in Morningtide, so you can only spend its mana on elementals. Like Gemstone Caverns, it only works in a very specific context. I'm going to jump ahead and mention Cavern of Souls, an Avacyn Restored card that made a lot of blue players so angry they ate their hats (or would have, if anyone wore hats anymore).
Like Primal Beyond, Cavern of Souls only produces colored mana for a single creature type. Unlike the Morningtide card, you choose the type when the caverns enter play. The hat-eating inducement comes from the fact that Cavern of Souls makes the cast spell uncounterable. Cavern of Souls feels it's narrow enough that it not only enables a specific set of spells, but protects them as well.
They aren't the only cards like this: Ancient Ziggurat isn't as picky as Primal Beyond or Cavern of Souls. It works for any creature, but it doesn't provide generic mana. Pillar of the Paruns functions identically for multicolored cards. Eldrazi Monument, Altar of the Lost, and Mishra's Workshop are all related, but a little bit out of scope.
Manalith, of the Shandalar Manaliths
Finally, there are the colorful mana-producing artifacts. With Prismatic Lens defining the standard for adding generic mana and filtering in one card, it's strange that the next step up is Manalith.
Manalith costs just one more mana, but adds mana of any color to your mana pool instead of merely filtering it. Darksteel Ingot technically came first, but Manalith is what I consider the "base model." Ingot adds indestructibility, Coalition Relic adds the ability to float mana, Vessel of Endless Rest lets you restock a card, Scuttlemutt adds a 2/2 body and some color-changing shenanigans, and Spectral Searchlight adds multiplayer versatility.
Family photo, 2013
Chromatic Lantern is the biggest upgrade, kicking the asses off of the gathered competitors. It obliterates the necessity of having different land types, filtering, and overriding a lot of the artificial obstacles that define the Magic mana system. Which is why I don't like it; it's boringly powerful.
I wanted to talk about the creature-based mana batteries of Diamond Kaleidoscope and SpringJack Pasture, but this was already long enough. The only reason I bring this up is because folks have actually been using the: "This post was" boxes at the bottom of each post to say they've liked this series and I thought, whoever you are, you might want to look into those too. Thanks guys.
Anyway, this is my last "It's the Magic" on this blog. This series is currently reposting on VanVelding.com for the next few weeks, but after that, I'll have a new bit up on how I used "Memory Magic" to try and get back into standard.
Until then, play for fun guys.