Gloom Leaf - Huge, Impervious, Thorns
Sekhma - Raksha Bond, Insulated
Snowy Owl - Nimble, Insulated
Plague - Virulence, Impervious, Aspect of Plague nice to have
Talon Banner (+2 Yellow, +1 Green, -1 Blue)
Put in fully-Traited Queen Mab in 4th if you want to arrest the AI looping with just one 4-Match. You lose the Devour protection, but it will make the deck much more accessible to a wider range of players and play styles. Frankly I think my initial suggestion to use Plague was not thought out fully and as useful as he is there, I think Mab ultimately will be better for more people.
Other logical 4th Troop alternates: Dracos 1337, Behemoth, Rock Troll
All troops are immune to Frozen; bottom troop immune to Kraken’s Devour; Gloom Leaf immune to Entangle and punishes hard for sky drop Skulls.
Owl deprives Purple and feeds it to Sekhma. Sekhma deprives Brown, deprives Blue. Owl self-loops and pollutes with Yellow, or feeds Red/Green/Brown onto the board, prioritizing situationally depending on what you need to add for a pending Sekhma cast, etc. Because Snowy Owl can make any color there is a lot of room for different board-control measures.
Start play by prioritizing the collection of Yellow for Snowy Owl.