Here are some top-notch free WordPress plugins you can use to display events—just as you described:

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✅ 1. The Events Calendar

• Latest update: Version 6.10.2 released March 4, 2025 (wordpress.org)
• Views: Monthly grid + upcoming events list (switchable views)
• Media: Supports featured images and full event descriptions
• Mobile-friendly: Fully responsive
• How to enhance: Use the free Events Shortcodes addon for clean grid/list displays with minimal styling (reddit.com, reddit.com, ve.wordpress.org)

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✅ 2. Event Calendar (MotoPress Timetable-ish)

• Clean UI: Offers Day, Week, and Month grid views
• Easy event linking: Clickable events open detail pages with images
• Responsive and simple: Lightweight, fast, and mobile-optimized

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✅ 3. Simple Events List / Pie Calendar (via Reddit suggestions)

• Reddit-approved: Users mention Pie Calendar and Very Simple Events List for fast, image-grid and list displays (reddit.com)
• Lightweight: No ticketing features, just elegant event display
• Minimal setup: Easy configuration via shortcodes or blocks

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📋 Before you choose, a few quick questions:

1. Do you want Gutenberg block support, or is shortcode-only fine?
2. Is image or video display in the detail pop-up essential for your design?
3. Do you need recurring events, or are these all one-off happenings?

Once you tell me, I can help you set it up with clean styles, modern shortcodes, or Gutenberg blocks. 😉

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Bonus:
To keep relying just on WP Admin and core edits, The Events Calendar with the free Shortcodes addon is probably your best bet—it ticks all your requirements (grid + list + media support + mobile UX).

Let me know what you prefer—I’ll walk you through installation, styling, and setup.