JHL
- A Java-based Hotline client.
- http://jhl.johnl.org

DefBot
- A very customizable automated Hotline client for server administration and user moderation.
- http://www.s-and-m-software.com/

Underline
- A variant of the OpenLine client for MacOS and Windows that supports blowfish encryption.
- http://www.hyperspasm.com/underline/

Avaraline Client List
- Client applications developed by Avaraline members for the Avaraline extensions to the Hotline protocol.
- http://www.avaraline.net/clients.php

Heidrun
- Heidrun is a Hotline client for the Macintosh Operating System that is module-based, letting the end user decide by how the client will look/feel/work.
- http://www.netsafir.com/~granma/

HotlineX
- Project responsible for the hx (mhx) client and its graphical front-end, ghx.
- http://hotlinex.sourceforge.net/

Fidelio
- Linux/Unix client that supports most of the latest Hotline features.
- http://fidelio.sourceforge.net/

SilverWing
- A Hotline client for BeOS. A version is available for the x86 hardware platform as well as PPC.
- http://hp.vector.co.jp/authors/VA013465/silverwing-beos/

Ripcord
- Alternative Hotline client
- http://www.mcbeen.com/ripcord/

inkSpot!
- A Macintosh Hotline client written in RealBASIC.
- http://www.inkspotting.com/html/inkspot/

Monica
- Monica is a Macintosh download utility for the automated downloading of files from the Internet using popular file transfer protocols, including the Hotline protocol.
- http://www.blackdiamond.co.za/bdmonica.html

Pitbull Pro
- A commercial Hotline client for the Macintosh Operating System that sports unique system administration features and connection engineering.
- http://www.hotline-tools.com/index.php?content=pitbullpro/info

HotPants
- HotPants is a Hotline 1.2.3-compatible client for Macintosh OS X.
- http://homepage.mac.com/haveblue/hotpants/

Frogblast
- Frogblast is a clone of the Hotline client software written exclusively for Macintosh OS X, using Apple's Cocoa APIs.
- http://ayanamichan.com/richard/frogblast/

BBSzilla
- An extension for Mozilla-based browsers that allows the user to connect to Hotline servers and other similar Bulletin Board Systems.
- http://bbszilla.mozdev.org

GtkHX
- A Hotline client written for Unix/Linux-like operating systems. It employs the Gtk+ environment for the front-end and utilizes a back-end based on the HX project.
- http://gtkhx.sourceforge.net