He also not only has double-strike, but if you land a hit on an opponent, you can put a goblin from your hand into the battlefield for free
The cards themselves can be found in The First Chapter set, but without the special 1st Edition Logo or D23 Logo on them
They help to clear blockers or push through the last few points of damage
Traditionally, combining Eyeless Watcher with Eldrazi Displacer is the best way to go infinite with a cost-reduction effect like Zirda's, although Eyeless Watcher itself doesn't have an activated ability
Said creature is, admittedly, just a 1/1, but the fact that it comes as a free extra alongside a land makes it worth playing in a number of decks, particularly those that can cheat creatures into play, such as Collected Company
Reanimator shells love it, as cards like Sun Titan or Unearth bring threats back to distribute counters across the board