Barnes has some outrageous outcomes, but even if he pulls something unexciting (eg vanilla 1/1 Onyx Bishop) it will still likely make your midgame Resurrect effects better on average.
Ragnaros the Firelord (if you're feeling lucky) allow you to immediately remove a threat, to buy you more time to play your other lategame options.
Soggoth the Slitherer is a giant sticky taunt to protect your face and high priority minions.
Dirty Rat buys you time in the early game, and when Resurrected you bypass his downside. Since the minion played by his battlecry is from their hand, playing a board clear after this will accelerate them running out of cards, especially if they were holding back to play against said board clears. Against control, Dirty Rat can potentially summon your opponent's win condition, which you can neutralise before they use the effect (e.g. any of the Old Gods, Alexstrasza, Grommash Hellscream, etc).
Dragonfire Potion is a fairly straightforward, efficient board clear against non-dragon decks. It kills most small to mid sized minions, and hopefully you can deal with any survivors.
Fight Promoter is a way to draw cards from your own deck without weakening resurrect effects.