Apps similar to Umamo include Inochi Creator, which is open source with a free version. Other options are nijigenerate and Live2D Cubism. In total there are three Animation Makers like Umamo for Mac, Windows and Linux.
Inochi creator is a framework for realtime 2D puppet animation. On this site you can find the reference implementation as well as the official tooling for creating and using Inochi2D puppets for VTubing.
Denmark
EU
Nijigenerate is an open source editor for the nijilive puppet format, which is derived from Inochi2D (v0.8) technology. This application allows you to rig models for use in games or for other real-time applications such as VTubing.
Japan
Live2D is the world's first drawing technology to enable 3D rendering of 2D images. This technology supports a variety of portable consoles and smartphones, and Live2D is already being utilized for games that take advantage of the unique characteristics of hand drawn artwork.
Japan
