Can colorless mana be generated from things that say "Add one mana of any color to your mana pool"?
One example card would be Coalition Relic.
Reasons:
- For example for sunburst spells, when the caster wants less of the sunburst effect, for whatever reason.
- You need to win the game with Scrapyard Salvo this turn, but you're one artifact in your graveyard short - casting a Sunburst creature as a 0/0 could be your only out