Here are my three cards that I think will be worth the most, you're more than welcome to post yours in the comments. Let's see who have the best ;) @acidyo, we have all seen your Sothek, so please choose another one ;)
Raving Fan (1 out of 24)
I got this in a rare pack, and it's a great card. It's really nice to have in your deck and you have chosen a god power that only costs 1 mana. Raving fan can get extremely strong combined with a Frontline on your board. Other than being a greta card, it also looks really good in diamond, which people value a lot.
Shadow Prince (1 out of 41)
This was one of the cards I drawed in one of my very first packs. One of the reason I think it could be worth at least a few ETH in the long run, is that it's a legendary in gold. There only exist just above 2300 of this cards (plain, shadow, gold and diamond) in total, and I have it in gold. I don't think it's the greatest card at all, but it looks really really awesome. The gold and the purple works really great together. Though it could be a very strong cards against an oppenent who plays a lot of spells. We will see.
Sonic Juggernaut (1 out of 24)
I think this will be the most valuable card. It's a super strong card, removing frontline, and has great strength and health, while looking super awesome, and of course it's diamond.
Please post your best cards, or the cards you think will be worth the most. If you're new to Gods Unchained, you can read my post here