Criteria: White and colorless cards with an activated ability that can make tokens at instant speed (unlike planeswalkers) and doesn't require any additional cost or criteria outside of mana to do so (like tapping, removing counters, or sacrificing anything)
Go ahead and give your Goblin Sharpshooter a Blight Sickle or Fists of the Demigod and start ripping into your enemies
Run 0-1 copies depending on personal preference
She comes in swinging, potentially growing to a 5/5 or bigger, and winding back time for you to enjoy those big abilities one last time
The five cards play much better than the land in terms of functioning as a source of mana without turn restrictions
This doesn't mean a player is at risk of not having enough lands to build a functional deck, but that they need to be more careful when selecting lands for their decks to ensure they can reliably cast their spells 'on curve,' which roughly means "at the earliest point in the game possible." One method of determining how many lands of each type to include involves counting up the colored mana 'pips' on each of the non-land cards (found in the top right corner of each card's casting cost) and using those numbers to calculate how many 'sources' of each color a deck needs
