Ambitious Farmhand 1W
Creature - Human Peasant
When Ambitious Farmhand enters the battlefield, search your library for a basic Plains card and put it into your hand, then shuffle. Coven—1WW: Transform Ambitious Farmhand. Activate this only if you control three creatures with different powers.
Creature - Human Knight
Lifelink "The cathars have taught me a lot, but I will never forget the hard and honest work I grew up with."
It's a decent ramp option in White, but gets better with Coven. Just be careful not to accidentally turn Coven off before the beginning of combat when you transform it.
Question: if you transform an attacker during combat, does it come back attacking? I would think not, but I'm not an expert on transformation in combat.
Yes, it will still be the same permanent on the battlefield, it doesn't "resets" the permanent instance the same way being blinked would.
If it's transformed during combat it's still attacking/blocking, if it's enchanted the aura will still be attached after transformation, if it's being targeted by a spell said spell won't fizzle etc. The only exception is of course cards that DO blink themselves before transformation, like Jace, Vryn's Prodigy.