You can get both plugins for under $20, Screamo is currently under $5 and the Mutant Delay is under $12. Bought them both as I’ve got a few WA plugins already. Mutant delay is a self ducking delay, especially suited to vocals. I threw it on a guitar part the other day and the results were really quite cool. The delay doesn’t trigger until the input signal is low enough and it can sound quite good when used right.
Screamo is a fascinating plugin that I’m not sure I’d use all that much. The distortion on this thing is quite nice on it’s own, but when you add the timed LFO stuff that it’s got built into it, you can end up with a talk box effect that’s quite pleasant.