I very much enjoyed HL1’s death match, especially the XDM Mod.
Fast Paced Death Match with hookshots, power ups, server editable modified gun properties, all guns and jump pack automatically on spawn.
It made the game very intense. Here is a video.
https://www.youtube.com/watch?v=y-5pL9iI2TM
This ^ is very enjoyable and is the reason I still sometimes play HL1 DM yet only about 5 or 6 servers are actively using this mod, but regularly have players in them.