Jürgen Müller

Just another mask! 
A very lightweight extension for the core/group gutenberg block. 
This adds an option, under the group blocks style tab, to add different top or bottom masks to a group block. 
You will love it. 🙂

Easy Mask

Boring straight lines? Add option to mask the core/group block with waves, slopes, spikes etc. A very lightweight extension for the core group block.

Ruslan Heorhiiev

This plugin adds a new field in which you can set the phone number mask or other to Contact Form 7.
Please notice that Contact Form 7 (version 5.0.3 or latest) must be installed and active.
A new field "mask field" will be added to the Contact Form 7 panel buttons.
Example: [mask* your-tel "mask" "Placeholder"]
Mask definitions: 
"_" – any numeric character.

Contact Form 7 – Phone mask field

This plugin adds a new field in which you can set the phone number mask or other to Contact Form 7.

Easy Mask vs Contact Form 7 – Phone mask field