Color doesn't matter. No Un-Sets. In case of a tie, one card tied for highest number suffices. I need such a card as a test case for a computer program involving MtG cards.
Progenitus has 10. This is easy to check in gatherer, just use CMC >= 10, and see that it's the max.
Draco has the largest generic mana number, at 16. (Observed using the same query.)
If you include unsets (I know you didn't want that, but for completeness, and because I love them) Big Furry Monster from Unglued has 15. And Gleemax has generic mana requirement of 1,000,000.
Don't really care about un-sets because I'm not going to implement them anyway. Jul 16, 2018 at 21:34
Still interesting to include them in the answer for completeness. Jul 16, 2018 at 22:52
1There's no maximum generic cost; a card with X in its cost can cost as much as the player chooses. Furthermore, there are ways that a card can cost more than its CMC: other cards can make it cost more, there can be a kicker cost, etc. Jul 17, 2018 at 17:34
Also, your BFM link doesn't work. It's gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=9780 Jul 17, 2018 at 17:48