Login form fill improvements
A lot of website forms work great, some more than others. Some don't work so great with TeamPassword's autofill.
For example, not every username/email input actually has a [type="text"] which make me having to type in a username or email address every time (systems like jenkins, mediawiki). I believe it's safe to assume you can fill an input without a type-attribute when it is one of two possible username/password input elements (i.e. excluding ([type="checkbox'"] and the like) in the same form and the other is [type="password"].
Other login pages have multiple [type="text"] and TeamPassword decides to fill in all of them, while usually (a fair assumption I believe) the first one is enough. A somewhat unusual example is proxmox. Its login page displays two additional inputs styled as dropdowns but their values are both overwritten with the username as well (it uses the ext js framework).
The Digital Orchard commented
I would add to this that any fields expecting an email address should ideally use [type="email"] to get the most optimal keyboard displayed on mobile devices.