I second the suggestion for Voicemod, although it hasn't crashed for me at all.

Generally don't use voice changing software when I GM, but taking part as a player in a 40K Warhammer game as a Space Marine, sorta made me consider using it. Worked really well, but it does help to join their discord and have a look at some of the voicelab stuff. I recommend VoiceMod Pro to get the most out of it.