While the final answer to this question will depend on what you deem as safe, Zoro.to is relatively safe when compared to other free anime streaming sites. It does not endorse malware or run any harmful ads. While the site does show unlicensed anime, it is not committing the majority of actions you might call unsafe.
Funimation is one of the best-known, longest-standing animation streaming sites for English users. It has long been considered a safe resource, and it is currently owned by Sony. If you think of Sony as a safe brand, you can extend that to Funimation. If not, Funimation is still one of the safest ways to stream anime.
While the answer to this question will depend on your particular safety concerns, it can generally be stated that this is a safe website. MyAnimeList is not participating in any directly malicious activity, and there is no malicious software associated with the site. It’s also committed to legally sourcing all content.
In most respects, AniMixPlay is safe to use. The site is not known to harbor any malicious software, it doesn’t collect any personal data that could be used against you, and there are no reports of the site managers behaving in sketchy ways. But, the site does not license anime, and that creates legal concerns.
Generally speaking, Anime-Planet is as safe as any website you can use on the internet. While it does provide resources to watch anime and read manga online, it does not engage in practices that put you at any definable direct risk. Your money and identity are safe when you use this site.
By all accounts, MangaOwl is a safe website and app for viewing manga on an electronic device. The app works within the legal framework of copyright regulation, is not known to harbor any malicious activity, and doesn’t even take personal data from you. It’s difficult to imagine a safer resource for reading manga.