Create and save artboard templates

I need artboard templates for the brand team: create and save an A4 brochure template, a US letter one-page sell sheet, and a square Instagram post variant, each with correct margins, bleed, and a locked slug area containing our brand fonts and logo. Name them Report_A4_Bleed, SellSheet_USLetter, and IG_Square_Template and store them in the company templates folder so my designers can start new documents from them.

Before I share templates with the design team, make them approval-friendly: surface the live text layers that must never be outlined, put the safe area guides in a visible color, add a small note in the slug explaining which fonts and color libraries to use, and lock all logo and grid layers. Also include a thumbnail preview and the exact document sizes so a non-designer can pick the right template quickly.

I've been asked to standardize artboard templates for campaigns but the product and social teams keep requesting slightly different sizes. I'm afraid I will create too many templates and confuse the team. What is the likely minimum set of templates I should keep, which variations are worth separate files, and how should I communicate naming and placement so people pick the right one?

Every quarter I find dozens of slightly different templates and designers using the wrong artboard sizes. Where am I losing control — naming, storage, or onboarding — and what three concrete habits will stop template sprawl and ensure the right template is chosen each time? Include naming rules and a quick verification step.