I was bored and decided to make a list of synergies.
Some of these simply mean that there are cards connecting the two elements, and some mean that synergy is possible even without such cards.
The list assumes that 1.24 will be released as it is now.
Wings + Phase Spider/Recluse
Fractal Vampires, Fractal Pests
Poison stall
Protected Phase Shield stall
Fractal Phoenix
Fractal Chargers
Fractal Life rush
Ray of Light - Hope
Anubis!
Mind Flayer / Ulitharid
* never realized that there is no aether card that uses another element; fractal makes a variety of duo+ decks available, though.
Flying Vampire Daggers
Flesh Spider/Recluse, Flying Arsenic
Flying Fahrenheit, Firefly, Unstable Gas
Flying Titans + Gravity Pull?
Firefly Queen
Divine Glory, Firefly Hope
Freeze + Shockwave
* Animate Weapon...
Parasite/Bloodsucker infection
Devourer/Pest Burrow, Gargoyle Stone Skin
Lycan, Liquid Shadow + Antimatter = enemy hitting him/herself
Control combo. used in many pvp decks
Adrenalined Vampires!
Skellies + Mutation
Bonewall/Boneyard/Vultures + Firestorm = Good
Otyugh
Flying adrenalined Arsenic
False God Morte (personally, a really stupid combo)
Mummy -> Pharaoh
Speed Poison (Chrysaora/Physalia)
Lava Golem/Destroyer, Basilisk Blood or Heavy Armor + Rage Potion
Pulverizer, Earthquake-Black Hole quanta denial combo
Stone Skins + Miracle = -_-
Graboid
Poseidon
Pillarless golem rush uses nova......
Discord + Black Hole
Fallen Elf/Druid
Chaos Power + Blessing?
* I guess it could be synergic with any element with nova/supernova
Graviton Fire Eater / Firemaster
Divine Glory
Steam Machine
Dark Matter (another stupid false god combo)
Mass Scarabs
Rustler/Leaf Dragon
Adrenalined Dejavu~
Forest Spirit/Spectre
Sundial
any other suggestions?