So somebody thought of playing the classic Test Subject combo deck, but had no idea for a decklist. Here I come to the rescue, with the optimized version.

Your combo is playing Regenerate -> Seance -> Topsy Turvy, all on Test Subject. In conjunction with Dragon Soul, you will be able to generate three 5/5 Dragons each turn, which will let you push enough damage versus most decks once you establish board control, but there's always Purified Shard just in case.

Why not Embalming Ritual? While it lets you get more Dragons immediately due to Ritual costing (1) as opposed to Seance's (2) Mana Cost, you lose out on actual infinite value that makes Dragon Soul worth running in your deck. Ritual only enables one wave of up to five 5/5 Dragons, and we don't bother including more copies of our combo just to get more waves of five 5/5s - we need deck slots for actual control tools that, conveniently, progress Seek Guidance.

Why not Power Word: Shield? It enables us to draw cards and dig faster for Shard, but we don't want to burn control cards or, better yet, Shard itself, from performing our combo nor do we want Radiant Elemental just to make it cheaper for Dragon summoning purposes.