Based on my knowledge some may have contributed to the I/O though:
- Aryo Activity Log

- WP-Ban❌
- Ultimate Member❌
- WooCommerce

- (A custom plugin I copy-pasted from somewhere to stop admin emails from being sent when any member changes their password)

- WPForms

- WP Mail SMTP

- The Events Calendar

- Roles & Capabilities

- Loginizer❌
- Advanced noCaptcha & invisible Captcha (v2 & v3)

For form’s, you can use google forms and embed that.