Discord now listen to all the conversation and then if there's a particular topic that's being discussed, the app will notify you about the topic that's discussing right now(or "highlight" of the conversation). I don't know if the "listening" part happened on server-side or client-side though.
If Android:
Aliucord -based on the Kotlin (old) version
Bunny/Pyoncord - The current best (and afaik only maintained) fork of Vendetta. Based on the new versions of discord
Tons of people use bluecord on mobile but I say to stay away from that cause sketchy.
I would opt for aliucord but if someone knows better clients that would be nice cause aliucord makes me die inside a little.
On desktop I use Vencord, I heard some bad stuff about it but I also heard that it's a troll, and I'm skeptical it would be sketchy. Only problem is it tends to stop working and needs repair very often.