If you play D&D online, there's a chance you use—or have used—Roll20. While it's far from the most versatile or powerful virtual tabletop (VTT) on the market (with others having far more extensive modding and addon support) it's both free and straightforward enough to use that I feel its popularity is deserved. You also probably haven't used its integrated voice chat system.
Whether it's improved since the last time I tried to use it or not, the fact remains that there are just better options. For example, Discord is a program everyone's already familiar with and setup for, while its servers work as great hubs to run campaigns out of, letting you keep channels for lore handouts, hold discussions, and passive-aggressively tag that one player who is always inexplicably having a nap when the session starts despite everyone being pretty sure it's like 3 PM in their timezone. We've all been there.
