Hearthstone - Pick up your cards and throw down the gauntlet!
Roll20 - Roll20 is a suite of easy-to-use digital tools that expand pen-and-paper gameplay.
ForgeMtG - Forge is an implementation of Magic the Gathering that lets you play against a computer AI opponent using most of the rules of a real game. You can construct decks for you and the computer to play with, or play in a draft or a sealed deck format.
Astral Tabletop - Create, host, and manage your tabletop role-playing games — online or in person
Infinity Wars - Infinity Wars is a Turn-based Strategy, Massively Multiplayer Online Role-playing, Collectible and Trading Card video game published by Lightmare Studios.
D&D Beyond - Official online toolset for Dungeons & Dragons tabletop gaming