JavaScript
Python
Java
PHP
Rust
Haskell
Typescript
Elixir
Spine
Synfig Studio
Creature
Spriter Pro by BrashMonkey
Animation Paper
DigiCel FlipBook
Unity 2D
CrazyTalk Animator
JavaScript
SpinePython - Python is a clear and powerful object-oriented programming language, comparable to Perl, Ruby, Scheme, or Java.
Synfig Studio - Just another WordPress site
Java - A concurrent, class-based, object-oriented, language specifically designed to have as few implementation dependencies as possible
Creature - Creature 2D Skeletal and Mesh Animation Tool
PHP - A popular general-purpose scripting language that is especially suited to web development
Spriter Pro by BrashMonkey - Spriter : an intuitive 2D animation tool for video game makers.