I think charging your chakra in a weird pattern repeatedly should be a method of breaking out of Genjutsu.

And that the sky should be the limit for the absolute insanity genjutsus can present. Localized, internalized, widespread, contagious. HUD/UI screwage, reversing player button layout, color inversion/desaturation/monochroming, straight-up fog of war on a variable scale, various levels of camouflage/invisibility, changing everyone around you into frightening monsters or black silhouttes to your perception, changing your camera lens dramatically, to the standard clone jutsu which is supposed to be an intangible genjutsu before you throw elements in...
Fake fireball jutsus or other strange attacks too, imagine fighting someone who seems to have every elemental nature until you realize some of them are intangible...
Genjutsus for silence or invisibility in the aflictee's peripheral vision would help stealth cheaply.
There's also disguising yourself as a thrown weapon, which was always a gold idea.

Beyond that, paralysis with any resulting effects, seeing a fire spreading everywhere or a false earthquake/tornado/storm... illusionary demon or monster summons to mix with the real ones...
There could be a Genjutsu that adds an extra 100% of fake damage that can knock out the opponent if it adds up enough.

Gonna sound like amongus levels of stale memes

I thought this was purely theoretical, no idea it actually existed before I joined...

Star Wars games (and others) also typically have a "perfect block" system. It would be difficult, but not impossible to perfect the necessary timing.

*sniff*... I'll probably never get to see summonable worms...