#extraplanar lens

Apologies for the small size of the graphic, first row doesn’t care about land type at all, simply giving everyone more. So if you have all 5 out and someone taps a single land, they get at least 6 mana.

Dictate of Karametra

Heartbeat of Spring

Mana Flare

Overabundance (which does deal one damage)

Zhur-Taa Ancient

Second row is a bit more exclusive, with Bubbling Muck, High Tide, and even Snowfall each only working for one turn and for one land type. Snowfall and Winter’s Night give a bonus to snow lands, but Winter’s Night is a bit of a double-edged sword. The third row is fairly exclusive as well. Extraplanar Lens you exile a land and only lands with that name make more mana (handy if your opponent’s lands don’t overlap yours). Gauntlet of Power is only for basic lands creating mana of a color you choose, which doesn’t matter much for a monocolor deck and or a deck that allows any land to create the chosen color by using either Prismatic Omen or Chromatic Lantern. Keeper of Progenitus is good for any non-Swamp/Island. Gauntlet of Might is for Mountains, and Vernal Bloom is for Forests.

If you tap a single Snow-Covered Forest and have the top row of cards along with Winter’s Night, Keeper of Progenitus, and Vernal Bloom, that single Forest nets you 9 mana.

Crypt Ghast and Nirkana Revenant are specifically for when you tap a Swamp. The rest of these (with exception of Sasaya, Orochi Ascendant as the other half of Sasaya’s Essence) don’t really mind what land it is you’re using (though Sasaya wants 7 lands in your hand before she really helps). As before, the image is a bit small, so the cards are:

Crypt Ghast

Nirkana Revenant

Vorinclex, Voice of Hunger

Zendikar Resurgent

Second Row is 

Mirari’s Wake

Regal Behemoth

Sasaya’s Essense (and the flip side, Sasaya, Orochi Ascendant)

That single Snow-Covered Forest from before? Along with that previous 9 mana, it gets another four here (possibly more from Sasaya’s Essence). This is why people raise eyebrows pretty quickly when you’re playing Snow-Covered lands. Because if you are, there’s a good chance you have a reason for it.

If you want to break these complimentary cards even further, there are a few options for untapping lands, such as Nature’s Chosen (enchanting a white creature) to get 2 more taps out of a single land. Or you could use Oboro Breezecaller and 2 of that 13 mana to return a second tapped land to your hand to untap the first (just make sure you tap the second before resolving this, so you get that mana as well).

Doubling Cube is especially noteworthy if you’re making large amounts of mana because it can be used simply to make more, or to help correct the colors when needed. For instance, if you only have one way to make blue mana (or used all but the last blue you have) doubling your mana can still allow you to cast Progenitus.