FZMM
A fabric mod that is mainly for editing or creating NBT of items in creative but it also has a few utilities
Head Generator
From this GUI, you can add textures to heads or modify them with 'models', and you can obtain the head in-game, visible to everyone (or you can also save the modified skin)
Head generator (overlay)
Some 'models' have parameters that allow you to do things like: change the color, adjust the height (for glasses, for example), or combine with another skin
Head generator examples
Operator utilities
Several items are added to operator utilities, and it can be accessed without OP (requires enabling the operator utilities tab from vanilla)
Banner editor
A simple GUI for creating and editing banners with ease
Banner editor (shield)
It also allows you to modify shields
Head gallery
Access to the large heads collection of Minecraft-heads
Text format item example
Player statues examples
Each of these 'Statues' is made up of 26 armor stands, each holding a head in its hand, and as you can see, it supports 128*128 skins