For those who use 3rd party SMS apps, what's a good one?

do you mean something like this?

https://www.twilio.com/sms

signal

signal/textra.

Signal, it seems like it is good privacy wise

Signal
It has a DARK theme. What more doI have to say. Oh yeah hecka encrypted.

QKSMS: Open source, material design, with dark themes. I honestly am surprised nobody else mentioned it already.

If you are on android :
https://play.google.com/store/apps/...

Or Signal. But even though its my IM of preference, I like keeping SMS and IM in separate apps.

The new SMS app by Microsoft is nice

It classify ur message automatically!

Like , promo,spam,personal etc

Textra

Silence from F-Droid. Supports E2E encryption to other Silence users.

Signal ♥️