maksbd19

This plugin will add a custom post type for event. In that you will be able to add/edit/remove events just as you do to your 
posts. There are 9 parameters are by default supported. These are-
<ul>
<li>Event date</li>
<li>Event Duration</li>
<li>Offical Website</li>
<li>City</li>
<li>State</li>
<li>Country</li>
<li>Event Gallery</li>
<li>Event Categories</li>
<li>Event Tags</li>
</ul>
And also you can add title, description, featured image to your event.
In the widget you can specify the title, maximum height of the widget, number of events to show and to display event from a 
category or tag.
Event state, city and countries are included in the search parameter. That means if someone search anything that matches with these 
meta values, they will show up in the search results.

Event Management Plugin

This plugin will add functionality in your site to add/edit/remove events and display them in a widget.

Siim Kirjanen

Create and manage online registrations with ease. Design your own registration layout and manage bookings.
SeatReg is built around a visual seat map. You design the layout in the map builder, add it to your site with a shortcode or share it as a direct link, and manage the bookings that come in. Visitors open the map, select a seat, and complete their booking.
It is commonly used for events and conferences, theaters and cinemas, classes and workshops, restaurants and venues, churches, and coworking spaces — situations where people reserve a specific seat or spot.
Features
<ul>
<li>Map Builder: Design your registration layout in the map builder. Create, delete, resize, and move elements, and add prices, legends, seat numbers, hover text, and custom colors.</li>
<li>Registration Overview: View your registrations and the number of open, approved, and pending bookings.</li>
<li>Customizable Settings: Control the booking flow through the settings, and add custom fields to collect additional data from customers.</li>
<li>Email Templates: Customize the emails sent to customers.</li>
<li>Export: Export bookings to PDF, XLSX, or TEXT.</li>
<li>Calendar Mode: Manage date-based bookings with calendar mode.</li>
<li>Responsive Registration View: Share a scrollable, resizable registration view via a direct link, or embed it in your pages with a shortcode.</li>
<li>Payment Integration: Accept payments through PayPal and Stripe.</li>
<li>Coupons: Create coupon codes that apply a discount during checkout.</li>
<li>Companion App: A web app for managing bookings — view them, scan QR codes, and receive notifications.</li>
</ul>

SeatReg

Create and manage online registrations. Design your own registration layout and manage bookings.

Event Management Plugin vs SeatReg