The Second Life to Discord text bridge I featured the other day is not available on the Marketplace (at least not yet), but there are already other options there. This one from Peter Strindberg is well-rated and has similar features:
Once activated, the relay announces itself in open chat, indicating how many lines of chat and for how long it will relay. This is in accordance with SL-ToS and SL-CS (see below), and gives any avatar present enough warning to stop talking, if they don't want their chat relayed. Consequently, the relay also announces when it stops relaying the chat. It only relays actual avatar chat, but ignores objects. The chat that appears in Discord uses the display name and profile picture of the avatar.
Strindberg tells he was careful to create a system that adheres to SL Terms of Service, as well as the EU's strict privacy rules:
"Under Europe's GDPR," as he explains, "you would need to get informed consent to process data on a 3rd party side. By keeping all processing within SL, there is no 3rd party data processing, other than on Discord's side."
As to how it works:
"The object inside of SL creates a webserver-on-a-prim, whose URL is then posted into a Discord channel. When you click that URL, a fancy webform opens, that is entirely hosted on the SL-object. Authorization and password-handling are all done inside of SL on the object. So the text you want to send FROM Discord isn't actually from Discord, but already entered in SL. And a username/password matching is configured by the operator of the system inside of SL as well."
Strindberg's system is modular, with a conference add-on and a Discord-to-SL addition.
If there are other options you recommend, please post in Comments!