As such, we needed a blue ability that is weak enough that using it ten-plus times isn't a problem, but that means enough that you care that you've done it ten times
Agrus Kos, Spirit of Justice Balefire Liege Bell Borca, Spectral Sergeant Excava, the Risen Past Nobilis of War Returned Pastcaller Spirit Mascot Stonebound Mentor Venerable Warsinger
Ghostly Prison and Propaganda get mentions here because they're essentially the enchantment versions of putting creatures up as blockers
To play it, youll exile a card in order to trigger its Harness ability, which essentially brings a creature card back from your Graveyard every turn
Being able to do this pretty much whenever you need, with practically no downsides, is ridiculously useful