Saw this video of what may be a rom hack of PS1 Doom or something with its own levels and assets.

The Imps are the Quake enforcers and there's a door that's literally a photo of some female model.

Doomguy should obviously remain silent outside of voice sounds but i think the reason why the Skulltag "hehee" sound is memorable is because it sounds close to his "voice" (The stock sounds id used in the original games).

Meanwhile, Brutal Doom and its ilk give Doomguy a rather "heavy" voice that sounds different, even if it's partially based off Quake 3's Doom (Specially with the taunt sound he had).

(Here he sounds a bit "fat" compared to the voice above, hope the VA doesn't feel hurt by my comment tho)

Meanwhile, that one Quake 1 port had a video comic where Doomguy officialy spoke for the first time (With an even heavier voice) and the PS2 port of Quake 3 had a "Caleb from Blood wannabe" type voice in the game's files but it does sound closer to his potential voice.

Then there's this Doom comic fandub which makes Doomguy sound like someone's impression of Ash from Evil Dead. Makes sense considering one of Doom's influences.

His voice in Eternal? It also falls under some of the above of making him sound "heavy" (Also, here's some unused voice lines from Eternal).

I just wanted to post about the Doom live reenactment from 1995 E3, with Mortal Kombat actors.

I believe there's other videos of this specific event with different angles (At least another one) but i could only find this.