What is the best tool to create videos like that

I would strongly suggest taking a look at krita which has the following points in its favor:

• Free, Gratis & Open Source (there are also paid options with automatic updates)
• Windows 7/10, Windows Portable, OS-X & Linux
• Supportive community including the developers
• Multiple Languages supported
• Pressure Sensitive Tablet Support
• Animation tools since version 3.0
• Layers
• Timeline
• Controllable Onion Skinning
• Animation Rendering (since 3.1) usint FFMPEG
• More animation features
• For some tutorials and examples see YouTube
• See this Deviant Art search for some examples of Krita work

The 2019 Mascot

The vision statement

Krita is a free and open source cross-platform application that offers an end-to-end solution for creating digital art files from scratch. Krita is optimized for frequent, prolonged and focused use. Explicitly supported fields of painting are illustrations, concept art, matte painting, textures, comics and animations. Developed together with users, Krita is an application that supports their actual needs and workflow. Krita supports open standards and interoperates with other applications.