Shut up and just give me the JSON scripts!

Collection of used and tested JSON scripts that you can use now

Most of these will need some tweaking, but you should be able to adapt these to your own usage.
Your list is grouped, and instead of the grouped column name being stated before your grouped name, it will show blank instead. It makes the list look cleaner and better for user experience.

For a grouped list, hide grouped column name and remove header

{
"$schema": "https://developer.microsoft.com/json-schemas/sp/v2/row-formatting.schema.json",
"groupProps": {
"headerFormatter": {
"elmType": "div",
"style": {
"padding-left": "12px",
"font-size": "16px",
"font-weight": "400",
"cursor": "pointer",
"outline": "0px",
"white-space": "nowrap",
"text-overflow": "ellipsis"
},
"children": [
{
"elmType": "div",
"children": [
{
"elmType": "span",
"style": {
"padding": "5px 5px 5px 5px"
},
"txtContent": "@group.fieldData.displayValue"
}
]
},
{
"elmType": "div",
"children": [
{
"elmType": "div",
"style": {
"display": "flex",
"flex-direction": "row",
"justify-content": "center"
},
"children": [
{
"elmType": "div",
"txtContent": "=' (' + @group.count + ')'"
}
]
}
]
}
]
}
}
}
Final Result
This creates a repeating sequential number for a field value. i.e. adding 1 to the previous number. This is useful for tracking lists or notes or RAG status lists.
I'm using a "TS00" prefix as an illustration. The idea is that it will add 1 to the next item created in the Reference number field.

CAVEAT - Note that if an automatically generated value is produced and line item removed, then the next number produced will carry on and not reproduce a previously produced number. If that makes sense.

Create a repeating sequential number in a number field

{
"$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
"elmType": "div",
"style": {
"box-sizing": "border-box",
"padding": "0 2px",
"overflow": "hidden",
"text-overflow": "ellipsis"
},
"txtContent": "= 'TS'+ padStart(toString([$ID]),3,'0')"
}
Change the second last line to either be blank or alter to have a different prefix. the "3 indicates where the next number position should be.
This code creates a clickable button alongside your document library. For any number of reasons, you may want to setup an action for your document or perform any kind of action relating to the item or other column values. Adapt the code below for additional actions, including aesthetics like font, colour, outline and look/feel.

Create a clickable button

{
"$schema": "https://developer.microsoft.com/json-schemas/sp/v2/column-formatting.schema.json",
"elmType": "button",
"customRowAction": {
"action": "openUrl",
"actionInput": "http://www.google.com"
},
"style": {
"background-color": "#0078d4",
"color": "#ffffff",
"border": "none",
"padding": "6px 16px",
"font-size": "14px",
"font-weight": "600",
"border-radius": "4px",
"cursor": "pointer",
"display": "flex",
"align-items": "center",
"justify-content": "center"
},
"children": [
{
"elmType": "span",
"txtContent": "Borrow"
}
]
}
Change the red items to suit, as well as the other aspects like fonts, weight, and justification.