Tap: Add 1 to you mana pool.
3, Tap, Sacrifice Havengul Fengraf: Return a creature card at random from your graveyard to your hand.
At the common level, I don't think mana producing, nonbasic lands, which have no drawbacks get much better than this. It makes colorless mana, it doesn't come into play tapped, and it has a sacrifice ability that can on occasion, save your creature loving butt.
The only real complaint against the card is the random factor when fetching a creature. This can be bad.
If your deck has creatures in it and if you can make use of colorless mana, you may want to consider Havengul Fengraf for your deck. But it must be said that the power of this card would be greatly increased if you knew exactly which creature you were bringing back from your graveyard. Because of this, you really want to fit this card in a deck with very few creatures. Specifically, you would get the greatest value out of it if you put together a spell heavy deck that only ran 3-4 copies of a single creature.
In other words, "random" is normally bad. By removing the "random" from the equation, this card becomes less bad. And you can accomplish this solely through deck design.