Shmeppy

A digital wet-erase mat with some virtual battlemap features usually found in a VTT such as fog of war, tokens, a ruler, and a laser pointer. This is perfect for people who like to draw their maps on the fly. Note that it only does hand-drawn battlemaps, not uploaded images.

I Met A Troll

Simply 16-bit map making & sharing with some VTT-like features, such as audio/video and the 5e SRD compendium.

**Planar Ally**

A complete, free virtual battlemap application with drawing, fog of war, dynamic lighting, image import, tokens, and a fancy ruler.  The GM will need to host it from their computer.

**3D Virtual Tabletop**

Somewhat similar to Tabletop Simulator, but it runs in the browser and it’s just for RPG maps.

Game Master Engine

This is a really cool 3-D map building/sharing tool, like Minecraft but just for RPGs (and specifically it looks better suited to fantasy games like D&D.)

Owlbear Rodeo

This is a dead-simple, no-frills simple map sharing application that you don’t even need to make an account to use.  There is no ruler, Fog of War, etc.  Interestingly, it has an experimental feature to beam music to your players from another tab in your browser (like Youtube,) however I haven’t personally been able to get that to work.