Udane, Herald of Warm Days 3RG
Legendary Creature - Spirit
When Udane, Herald of Warm Days enters the battlefield, you may discard a card. If you do, draw 2 cards.
If you would draw a card, you may instead add 1 mana of any color. Until end of turn, you don't lose this mana as steps and phases end.
You'd want a "Until end of turn, you don't lose this mana as steps and phases end." clause so that if you are drawing off triggers in combat, etc, you can still use it in your main phase.
Its a neat card, though I think it's not very close to Bloom. The strength of Bloom was the drawing feed you cards to discard for mana which you then spend to draw even more cards (a la Prosperity), so you were getting two mana per card and then getting one card per mana, doubling your return each cycle. This is trading cards for mana 1-1, which is unfavorable (trading one mana to gain a card is very strong on the other hand).
If you want to make this more Bloom-esque, make it, "Whenever you draw a card, add one mana of any color. Until end of turn, you don't lose this mana as steps and phases end." That would be far more an engine like Bloom was, but its rare to get a card for 1 mana anymore so it won't spin up to combo as easily.