At this moment you can change favicon.ico by replacing /usr/local/psa/admin/htdocs/favicon.ico, however it will be replaced on Plesk update.

It is also not possible to make it permanent using custom theme from Plesk branding guide.

Please make a way to customize favicon.ico on permanent basis

As you know, WordPress Toolkit can update plugins and themes installed only from WordPress.org. Paid plugins installed from vendors' websites cannot be updated using WordPress Toolkit.
It's not convenient to update plugins from WordPress.org in the WordPress Toolkit and log into WordPress admin dashboard to update paid ones, so please implement this feature.
Especially considering that it's possible to update both free and paid plugins in the WP dashboard (in the menu "Updates").

The actual MailQueue status is useless, becaus the "status" of the email isnt viewed. This contains the important information for mails with problems.... Please expand it with the status, like it is done win Webim for example

Plesk Obsidian introduced the Dynamic List View Mode and some of our customers are having problems understanding the new GUI.

It would be very helpful to configure the View Mode at the Service Plan level:
- Disable the possibility to change the View Mode
- Configure a default View Mode

add HTTP/3

No suggestion, but a critical, urgent, overdue feature request, as described in many "suggestions" since years:
Secure
mail.customerdomain.tld
webmail.customerdomain.tld
with Let´s Encrypt certificate without having to set the DNS A Record for
customerdomain.tld
to the mailserver IP.
And withouth having WAF disabled (SSL It 1.20 is being blocked bei Comodo (free) and Atomic (free) rules, other not tested yet).

Plesk PHP handlers should have the latest libicu package version for better compatibility with newer versions of web apps such as Magento

Free version of Enterprise Litespeed, it would be nice to use lsphp+Openlitespeed+LSCache (free) within Plesk.

A a reseller I would like to be able to create my own specific plug-in 'sets' for my WordPress customers. Normally this should be done at this level, not by the 'top level' administrator.

Maybe it is possible to use the same tab and visualize created sets from resellers with an icon.

Implementing the new standard WebAuthn would be the best solution for 2FA.

I've installed 1.4 manually and it works without problems.

In Plesk Premium EMail it is not possible to send or receive mails on the address of the public mail folder's name.

It should be possible to send mails from the public mail folder and mails received in it should be visible for other mail-users as in Microsoft Exchange.

Currently, management of additional Apache/nginx directives is available for Plesk Administrators only.

With Apache, it is possible for users to add custom directives via .htaccess file.

However, when running a Plesk server with nginx only hosting and a large number of customers, it takes a lot if time to configure nginx directives manually for each.

It is clear that additional Apache/nginx directives fields are hidden from Plesk users for security reasons, but it would be great to have an ability to enable this feature at your own risk.

Previous same suggestions that have been marked as "declined":
https://plesk.uservoice.com/forums/184549-feature-suggestions/suggestions/34285378
https://plesk.uservoice.com/forums/184549-feature-suggestions/suggestions/38760889
https://plesk.uservoice.com/forums/184549-feature-suggestions/suggestions/19087582

To allow Plesk to work properly with multiple browser tabs under the same user session.
For example with Google Chrome, log in once at Plesk as a dmin then:
Ctrl+Click on Tools&Settings, and then also on Clients
On the clients page, click on "Log In as Customer" and wait for it to load.
Go to the other tab (Tools&Settings) and click somewhere. It will be automatically redirected to Client, instead of staying as Admin for this tab.

Add mcrypt module to Plesk PHP 7.2 and newer.
For previous PHP versions it's included out of the box.

Mcrypt 1.0.2 natively supports PHP 7.2+ (https://pecl.php.net/package/mcrypt/1.0.2)

It's, for example, required by Prestashop 1.7.x, which is quite popular among Plesk users.

At this time, access to spamfilter settings for a mailbox are only possible for admins and website owners. Pls make it possible for logged in mailbox users to access and edit there own spamfilter settings.
It's very important, because on website's with many mailboxes, the admin often cannot support all users in setting up there spam settings.

Please provide Digital Ocean Plesk 1-click installation image on CentOS 8.

CentOS 8 is supported since Plesk 18.0.25: https://docs.plesk.com/release-notes/obsidian/change-log/#plesk-18025

As of now, feature with 178 votes is available in Plesk Onyx 17.9 Preview only: https://plesk.uservoice.com/forums/184549-feature-suggestions/suggestions/17924536-fail2ban-now-supports-ipv6-please-upgrade

It would be awesome to have this feature available on earlier versions of Plesk Onyx without the necessity to wait until Plesk Onyx 17.9 becomes stable.