Tapping for mana is an activated ability, so with this, you basically duplicate your workshop on turn 1 and can have stupid mana by turn 2.
Outside of that, I was thinking Tomb of Urami, but you'd still have to sac the tomb and then that shuts off the copied ability on this thing, so that won't do any good. Basically this will be a second strip mine or ramp land in 99% of cases. For the 3 mana, you're better off with crucible if you are wanting extra strip mines, so this is just a 5th Mishra's workshop, really.
This plays well with some already proven lands, like mishra's workshop, tolarian academy, mishra's factory, karakas, and maze of ith.
It also plays well with cards like volrath's stronghold, bazaar of baghdad, Library of alexandria, gaea's cradle, and the longest shot I could find that might be useful was vault of the archangel.
Other than mana ramp, or doubling down on golos utility I'm not sure it finds a home in shops. I also don't see any other archetype wanting it for utility since it is rather slow and clunky without a tutor engine like golos.
Still a neat card, and something to keep in the back pocket for when wizards slips up and make a truly abusable land to combo with it.
This counts all lands in the battlefield, including opponents. This could be clutch in a Factory War, or just stealing a few draws off an opponents library/bazaar. A welder deck would (viably) get double utility off of Dredge/Workshop opponents out of this.
@serracollector That could be good, but it's difficult to justify how this would be playable maindeck by copying your own lands. Bazaar is the most abusable, but most bazaar decks can't reliably generate 3 mana. If you are not running workshop or bazaar yourself, this is pretty unplayable. It's also really bad to depend on your opponent's deck to give this thing any utility. BEST case scenario is this is used in a workshop deck that duplicates your own workshop turn 1 and happens to copy a bazaar or tolarian your opponent has. But Christmasland scenarios are not good for main decking otherwise hot garbage.