You can technically insert hundreds of different meta tags into a page's <head>, but the vast majority are either obsolete or irrelevant to search and user experience. In active SEO work, you'll realistically interact with a core set of 5–8 tags on every project. The essential tags are title (technically not a meta tag but grouped with them), meta description, meta robots (noindex, nofollow directives), viewport (mobile rendering), and charset (UTF-8 encoding). Beyond that, Open Graph tags—og:title, og:description, og:image, og:url—control how pages display when shared on Facebook, LinkedIn, and most social platforms. Twitter has its own set (twitter:card, twitter:image), but those often fall back to OG tags if absent. Other tags you'll encounter occasionally include canonical (link rel, not meta, but in the same bucket), meta refresh (redirect hack, mostly deprecated), meta keywords (ignored by Google since 2009), geo tags for local businesses, and various Google-specific tags like nositelinkssearchbox or notranslate. Bing respects a few tags Google doesn't, but the overlap is 95%. At Ottawa SEO, we template 6–8 tags across our 500+ domain portfolio: title, description, robots, viewport, charset, og:title, og:description, og:image. We add canonical on paginated or duplicate-risk pages and occasionally use hreflang when running multi-language projects for Montreal or international clients. Everything else is clutter unless you have a specific technical reason—like meta refresh for a JavaScript-disabled fallback, which almost never happens in 2025. The practical takeaway: don't waste time hunting for exotic meta tags to boost rankings. Google reads five tags that matter for SEO (title, description, robots, canonical, hreflang) and ignores most of the rest. Focus on writing strong titles and descriptions, setting correct robots directives, and ensuring OG tags populate so your content looks good when shared. That covers 98% of real-world scenarios.