What are some good Maps with a lot of custom monsters? Like ones from Hexen and moded quake monsters?

Oh yes yes. With monsters from other Quake mods and with an axe model that can shine and blink red.
Oh and if possible with particles all over the place. That would be truly awesome.

No, not at all!. There are some very bad custom skin mods for monsters indeed. However I did really like those cyber ogres and Hexen 2 monsters work well with some medieval type maps imo…
Plus I like the Gremlins and variations on Hell knights… Adding armagon in is always a bonus too…

Try searching for “quoth” in the database.

I’d recommend you start with Red 777: