Card Hunter [official site] is available on Steam right now. It will be one of the best games released on Steam this year just as it was one of the best games of 2013, when it launched as a browser-based free-to-play CCG/RPG hybrid. The development team includes former Irrational, Popcap, Looking Glass and Magic: The Gathering folks and the game is every bit as good as their combined back catalogue suggets it might be.
Go. Play it now.
Here's my review from way back when. My thoughts haven't changed a great deal. I haven't played for a while and I'm looking forward to seeing how much I remember. The new expansion looks great, adding sci-fi equipment and settings. The whole game is in the form of a fictional tabletop RPG and the cross-genre pollination is exactly the kind of thing you often find in the supplements. It's a lovely fit, right down to the electronic games master.
A quick note on monetisation. I usually run a mile when I see a 'free-to-play' game but the occasional pleasant surprise like Card Hunter helps to temper my instinctive flight response. You can play Card Hunter without spending a penny but if you do want to throw some money to the developers, there are cosmetic cut-outs to purchase as well as subscriptions that boost the loot you receive. I've spent a fair few quid on Card Hunter over the last couple of years but it's still worked out cheaper than what I'd happily have paid for it, and I've never felt that the pace is unreasonably slow when I haven't had a subscription for superior loot. You're paying to improve your chances within the subscription period rather than shelling out a fixed sum for equipment that's otherwise unavailable.
It's a game that deserves a massive audience and hopefully Steam will help. If you already have an account, all of your progress and characters will work on the Steam version, which uses the same logins. I didn't realise the expansion was out today and I have actually cancelled plans to go to the pub so I can play. I never do that.