This question is different from donating to any specific user.
If the SE network can receive some extra funding; they can (and should) the following improvements:
Increase the server strength, and avoid server crash or jam.
Increase the memory space to safely host more question-answers.
Evolving multiple, powerful sync and back-up networks, at different part of world; so that if the data in the site get damaged anyhow; the sync and back-up network will recover it.
Installing more long-lasting and good-quality hardwares.
Better troubleshooting and hardware repairing.
Better feature-update and support service.
Better maintenance of all aspects of the site.
This similar question; does not tell about requesting a button. Also another similar question, also not requesting a button; includes a PayPal option or a contribution code; but does not tells about adding a button.