Thekal Crazy Heal Combos

Plan A - the early game winner

At first I was looking for a stable way to use High Priest Thekal - Molten Giant combo as a valid deck strategy: Call to Adventure.

With CtA we a have reasonable chance to get Thekal early game and reduce our life to 1. EVERY SINGLE GAME MULLIGAN FOR THEKAL OR CTA AND MOLTEN GIANT! More than 50% of early game Molten Giants are auto win.

Plan B - removals and mid game

The Thekal - CtA - strategy restricts this deck to have only minions with cost 4 and higher - that means no Wild Pyromancer + Equality :-( . If we are unlucky at early game we can use Paladin's great removal spells like Equality, Consecration and Shrink Ray. We can also use Bloodclaw and Truesilver Champion which both support remove and heal strategy.

We have a fair amount of mid game minions which can provide good pressure on the opponent's life points. With Blessed Champion there is often the chance to make 16 damage with a surviving Zandalari Templar, Ragnaros, Lightlord or Molten Giant.

Plan C - crazy heal combos

The most underrated heal card imho is Lightforged Blessing.

early Molten Giant will recover your life very fast
The Glass Knight will re-equip itself with Divine Shield every time dealing damage and your life isn't full (try it and you will have fun, I promise)
Blackguard with Lifesteal continues healing your hero and clearing the opponent's minions until their board is empty or your life is full (even more fun, just try it!)

Keep in mind: Lightforged Blessing costs only 2 mana and is a Twinspell... so much value

Plan D - Hakkar and Prince Liam

I saw that strategy on Out of cards and I really liked it. Play Hakkar, the Soulflayer when you have mana and time. With 9 attack the enemy must react. As soon as you get the feeling that you have to stop the blood corruption, play Prince Liam. Depending on your number of Corrupted Blood copies, you will get useful late game legendaries and the enemy will continue bleeding.

Replacements

What to remove?

don't replace High Priest Thekal, Call to Adventure, Molten Giant and Lightforged Blessing as they are the core of the deck
Rebuke and Time Out! are not necessary but really helpful against combo decks and Big Priest
Hakkar, the Soulflayer and Prince Liam combo is only needed in long lasting endgames (meta-depending)