Below are a few effects shaders I like, in ISF format. I found a lot of them on http://shadertoy.com, and I converted them to ISF using my online tool: https://magicmusicvisuals.com/utils/shadertoy_to_isf.php
I'll update this list as I find more. Most of them haven't been edited in any way, so I can't guarantee they will work on all systems.
If you need help using ISF shaders in Magic, check out this topic: viewtopic.php?f=3&t=412
Monochrome dither:
CRT (old TV):
Color channel glitch:
Another CRT (more distortion):
Crosshatching:
Ripples:
Refraction:
PixelateGrid: