I fully support this feature request and would like to extend it a bit.

When creating a new login in Proton Pass, I would love to have:
1. A full email picker
A dropdown that shows all my existing addresses and aliases, including:
• Main Proton addresses
• Addresses from all my custom domains
• Existing hide-my-email aliases
This should be one unified list, so I don’t have to type or remember anything. I just pick the right identity for that service.
2. Predefined usernames (handles)
In addition to email addresses, it would be very helpful to have a list of predefined usernames that I can manage in my account settings.
• These usernames would be independent of any email address.
• When creating a login, I could either choose an email from the picker or pick one of my predefined usernames (or both, if the site separates username and email).

Why this matters:
• Users with multiple domains and many aliases need a quick way to choose the correct identity.
• It keeps usernames and email usage consistent across services.
• It avoids manual typing, guessing, and copy-paste from elsewhere.

In short: when creating a login, Proton Pass should offer a structured identity picker:
• choose from all existing emails/aliases (including custom domains), and
• choose from a set of predefined usernames.

This would make identity management in Proton Pass much more powerful and efficient.

Super important as it takes away any current headaches of using multiple email adresses. Currently it is a headache trying to remember the different ones (when you have 5 different ones to separate everything into categories) but having keypass suggest the different ones (with a note for example what the email is for if for some it is not clear) would make it far better to keep up this higher security "model"

That would be a great feature when having multiple email addresses for various purposes :)

This is a table-stakes feature for password management. Saves a lot of time, esp if you don't save your login information on sites you visit frequently.

When creating a new login and selecting the email field, you can choose between a new alias or the proton email. i would like to be able to pick other email addresses (apart from those two) used in already existing logins

Whenever I use the Proton Pass browser extension's email autocomplete, it only shows my main Proton Mail address, and the "create an alias" button, but since I use Proton Pass' free plan, I can only create 10 (and already have).
It would be useful if the e-mail autocomplete list would show all of my e-mail aliases, so I can get to using them in a single click like with my Proton Mail address or new aliases.

When I have to fill in an email address in a form that is not associated with a log-in, Proton Pass offers me the choice of using my real address or a mail alias. If the mail alias already exists and I select it, I get an error because the alias cannot be created. Instead, the existent alias should be used, optionally with a warning that it already exists.

Drop down list of current email addresses used in Proton Pass
I would like to see a quicker/productive options for quick references for email addresses used in Proton Pass. I am not talking about Proton Mail! I am talking about a quick reference for when you create login need to select a email instead of default email that is applied to Proton Pass.

When I want to create a new entry, I would like to have a dropdown menu in the email/username section where I can select my created Proton email addresses. I have created some aliases for different areas in my life, such as household, streaming, gaming, shopping, social media and some others. Here is a case: If I want to create an Amazon login that I then select my ‘shopping@proton’ in the dropdown menu or a Netflix login my ‘streaming@proton’. With perhaps an addition in the settings that you can enter which e-mail addresses appear in the drop-down menu.

The background to this is that I'm gradually switching from all the different emails and what feels like hundreds of accounts that have accumulated over 25 years to my Proton addresses and that would make it much easier.

I have multiple Proton email addresses. When using Proton Pass to create Aliases, it only allows me to use my default email address for forwarding. It would be great to select my other Proton emails to forward to -- rather than my primary/default. This seems like it would be a relatively easy fix since the the structure is already there. This is helpful for organizating/segmenting types of emails received from different organizations/companies.

https://protonmail.uservoice.com/forums/953584-proton-pass/suggestions/49128704-multiple-email-address-suggestions-when-registerin

I agree, plus I've merged a few ideas into one suggestion here

Proton pass always suggests the default email (or simplelogin). We should be able to choose any of our email addresses as the default suggestion.

In my case I only use the default email for logging into the Proton account. I never use that addess for anything else so I would prefer not to have that as an option at all!

Possibility to choose between multiple email address on new credential creation. This feature can be useful when you use mutliple email address on different websites.