I like this suggestion. I've found myself occasionally wondering about some of these variables represent.

I however suggest that if we steer away from the "*Ref" suffix because we have many kinds of Refs so the naming could become confusing.

How about we instead use the "Template" suffix? And at that point, if we are making a recommendation for naming of ng-templates, we can as well make a recommendation for suffixes of elements, components, and directives.

Here is a draft proposal:

<!-- template variable reference for ng-template is suffixed with "Template" -->
<ng-template #usefulTemplate>
  I'm super useful!
</ng-template>

<!-- template variable reference for components is suffixed with "Component" -->
<my-hello #helloComponent></my-hello>

<!-- template variable reference for DOM elements is suffixed with "Element" -->
<p #pElement>
  Some interesting paragraph...
</p>

<!-- template variable reference for exported directives is suffixed with "{DirectiveName}Directive" -->
<form #profileNgFormDirective="ngForm">
</form>

What do you think?

Btw, if we go ahead with this change then we should also update the following guide to conform to the new style:
https://angular.io/guide/template-reference-variables

I had forgotten about the others :)
Seems reasonable to suffix them with that they are.

Perhaps some elements merit special treatment.

<!-- template variable reference for input elements is suffixed with "Input"  -->
<input #phoneInput placeholder="phone number">

Hmm maybe that's going overboard. The $ suffix from observables comes to mind.

Now this isn't supported, but perhaps a # suffix

<input #phone# placeholder="phone number">

<button (click)="callPhone(phone#.value)">Call</button>

The suffix seems a bit magical. Why not just phoneInputElement?

Also, for the purpose of distinguishing component properties from template references, what would a component do which takes a template as an input? Naming it itemTemplate seems logical, but template-side nullifies the intention.

FWIW I'm not a fan of Hungarian notation in variable naming. I don't really know that this is something that belongs in the Angular style guide versus something that individual teams can decide for themselves.