Mana Confluence

{T}, Pay 1 life: Add one mana of any color.

Heartbeat of Spring

Whenever a player taps a land for mana, that player adds one mana of any type that land produced.

Kynaios and Tiro of Meletis

At the beginning of your end step, draw a card. Each player may put a land card from their hand onto the battlefield, then each opponent who didn't draws a card.

Sol Ring

Collective Voyage

Join forces — Starting with you, each player may pay any amount of mana. Each player searches their library for up to X basic land cards, where X is the total amount of mana paid this way, puts them onto the battlefield tapped, then shuffles.