Roll20 - Roll20 is a suite of easy-to-use digital tools that expand pen-and-paper gameplay.
D&D Beyond - Official online toolset for Dungeons & Dragons tabletop gaming
Astral Tabletop - Create, host, and manage your tabletop role-playing games — online or in person
Talespire - TaleSpire is an online, digital, graphical way of playing classic P&P Role-playing games with...
MapTool - MapTool is a 100% community driven and 100% free to use online, multiuser, networked, graphical, interactive, programmable virtual tabletop.
DiceCloud - Realtime D&D 5e Character Tracker