Its similar with spell cards, except some of them are 'instants, meaning they can be used anytime - such as in response to another players move
Rishkar, Peema Renegade + Jiang Yanggu, Wildcrafter Rishkar, Peema Renegade and Jiang Yanggu, Wildcrafter arent exactly the same card, but they fill a similar role as cheap plays that scatter around a few counters and, more importantly, turn your team into mana dorks
GR Gold Rare El Dorado Adelantado X TRAP If you control an "Eldlich" monster: Activate 1 of these effects
Land search cards like Evolving Wilds help you to get the mana you need while also churning through your deck faster
In four- and five-color decks, now we're mulliganing aggressively until we find one in our opener
The best ones are either cheap, like Sol Ring, or do something other than produce mana