Communities like Handy-FAQ.de and 4pda.to have dedicated threads for Nokia E5. They host "Signed" themes (no certificate pop-ups) that install without hacking your phone.
In the last five years, Symbian nostalgia has moved to Telegram. Search for "Symbian S60v3 Themes." Bots often provide direct download links to .sis files ready for installation. nokia e5 themes
A step-by-step guide on to bypass certificate errors. Troubleshooting installation issues for .sis files. Communities like Handy-FAQ