28 cards preview from TouchArcade
25 cards preview from PC Gamer (Midiron's Head and V-07-TR-ON cards are new here compared with TouchArcade's)
EU Battle.net's Goblins vs Gnomes Official Page (Emergency Coolant, Finicky Clearfield, Reversing Switch, Rusty Horn, Time Rewinder and Whirling Blades are new compared to TouchArcade's preview) Update: The mentioned cards along with Armor Plating are "Spare Parts" token cards from Tinkertown Technician and Clockwork Gnome. Source: Reddit
If I did not recall wrongly from going through all the above card previews, we have about 36 cards so far. There are a lot of random effects and it will certainly make the game a lot more interesting and fun. However, I'm hopping for the remaining 90 or so cards to contain more "skill-based" interesting cards. The expansion is coming out in December and will be available in a separate pack from the existing set. Update: Arena will be rewarding new card pack once expansion drops. Source: Ben Brode, Senior Game Designer Twitter and Reddit.
Here's a hands-on from TouchArcade featuring mostly the previewed cards:
TouchArcade hands-on
*New* Blizzard's Set Teaser Page revealing new cards based on Twitter voting.
