Lemmy itself allows you to block communities, instances, and users. But it does not support filtering by keyword, e.g. filtering out any post with the word “platypus” in the title regardless of where it was posted or by whom. With help from the comments below, here are some third party Lemmy clients that have their own implementation of keyword filtering:

• Connect
• Eternity
• Interstellar
• Raccoon
• Summit
• Sync
• Tesseract
• Thunder
• Voyager

Do NOT support keyword filtering:

• Alexandrite
• Jerboa
• Lemmy UI
• mlmym
• Next
• Photon
• Quiblr

Comment anything I have missed or mistakes I made

https://feddit.uk/post/18770058

Voyager does this

Voyager does keyword filtering. It’s been awesome since the shit stain won, kept my feed to more sane/less doom scrolly content.

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lemm.ee##div.post-listing:has(span:has-text("/Trump/i"))

Put that into your adblocker custom filters. Just change the lemm.ee to lemmy.world (or what ever instance you’re on)