Abonner for at downloade
Font - L4D1 BOLD

Disclaimer: to avoid complications with workshop version of this, you can get ALL font mods at this link
http://l4d2.gamebanana.com/guis/27825

this is an old version where all the text is bold.

Be advised that for current build of L4D2 & workshop, you need to use the following command to load it from console:

alias reloadfont "mat_setvideomode 1920 1080 1; mat_setvideomode 1920 1080 0"

-you need to replace "1920 1080" with your l4d2 resolution and then add it to your autoexec.cfg in /cfg folder.
If you don't have an autoexec.cfg in
steam\steamapps\common\left 4 dead 2\left4dead2\cfg\
you can create a .txt file and rename it to autoexec.cfg, then edit it with any text editor like notepad.
More on mat_setvideomode here:
http://pastebin.com/YEiMzJT0

After the command is added to autoexec / aliased , you'll be able to execute it from console (by typing "reloadfont" )
in order to load / activate the font mod.

You can also use the reloadfont button feature of my "Game Menu" mod for that matter.