Many developers offer high-quality, modern, bootstrap-based MyBB themes for free on GitHub. Look for well-maintained repositories with active communities.

The MyBB community mods site offers hundreds of free, safe themes.

If a theme forces you to display links to spammy websites and breaks if you remove them, it is likely malicious. Safe and Legal Alternatives

At first glance, downloading a nulled theme (a premium theme stripped of its license verification and distributed for free) seems like a smart way to save money. But this is a classic case of "penny wise, pound foolish." In this long-form article, we will dissect what nulled themes are, the specific security, legal, and ethical risks they pose, and provide safer alternatives.