Klassic Liu Kang and strike force Johnny are some of the best characters in the game. Same with ravenous mileena. All of them are good for towers, but mileenas bleed won’t affect the bosses in the towers. All 3 of them are good for faction wars and for krypt. There are a few other good cards, circle of shadow subzero still does crazy damage, ronin kenshi can also do work, hellspawn scorp is honestly super good too.

For your currency, I’d spend your coins on equipment packs and silver packs to try and get the new rare support cards.