Free
Roll20
Roll20 is a browser-based virtual tabletop platform that allows players to run and participate in online tabletop RPGs with tools like maps, dice rollers, and integrated voice/video chat.
Free
D&D Beyond
D&D Beyond is an official digital platform for Dungeons & Dragons 5th Edition that provides tools for character creation, campaign management, and access to official game content.
Free
Steam
Steam is a digital distribution platform by Valve Corporation that allows users to purchase, download, and play games, as well as connect with other gamers through social and multiplayer features.