MineMention
MineMention is a Minecraft mod that adds a mention system to chat, allowing you to precisely specify who should receive your messages.
With this mod, you can mention specific players or user groups. When your message contains at least one mention, it will only be visible to those you mentioned, not to all server participants. You can mention multiple people at the same time.

When you type the @ symbol, auto-completion activates to help you quickly select the desired mention:

Built-in Mention Groups
MineMention includes three standard groups that can be mentioned, and other mods can easily add their own:
@everyone— mentions all players on the server@here— mentions all players in the current dimension@near— mentions all players within a 100-block radius
Reply Function
You can click on any mention or sender name in chat to quickly write a reply:

Smart Default Mentions
If you don't want to constantly type @PlayerName when frequently communicating with someone, use the /d PlayerName command to set default mentions. These mentions will be automatically applied if you don't specify them explicitly in your message.
To change default mentions, execute /d with a list of mentions as arguments (without the @ symbol at the beginning). The /d command without arguments resets settings to @everyone.
Current default mentions are displayed above the chat window:

Configuring Special Mentions
If multiple mods register identical special mentions (often happens with @team), none of them will be available by default. This can be fixed in the configuration. In the mentions section, you can specify which special mention should perform which function. The key is the mention name, and the value is the action identifier.
All mentions except @everyone can be redirected. If you set the value to minemention:none, the mention will be removed.
Configuration example:
{
"mentions": {
"here": "minemention:none",
"near": "minemention:none",
"close": "minemention:near"
}
}
This configuration will remove @here and rename @near to @close.
Built-in mention identifiers: minemention:everyone, minemention:here, minemention:near, minemention:ftb, and minemention:none.