My rule of thumb is if there are a lot of decks that fold to three 3/X creatures on turn two, Dredge is a good choice
They are rare monsters primarily obtainable as in-game secrets hidden on specific map tiles
[1] If this card is in your hand: You can target 1 Spellcaster or Fusion monster you control
We've seen the card be broken from formats like current Standard, thanks to its Foundations reprinting, all the way back to Legacy, where it shows up alongside Show and Tell
The ability is simple and doesn't give you a whole lot of value to play with
The fan, Urijah Mayle, was into Yugioh many years ago, and says he has a soft spot for the old cards, but now only plays Magic