Well the copy technique is fairly underused, however if I ever use the bio in the ninja world, it does allow you to copy techniques and retain the knowledge, with the eyes of hatred speciality specifically. Which can lead to some interesting technique stealing potential, it's like a rent a custom.
In regards to the genjutsu and why I like them, heaven and earth change is one of the coolest most underused things in the RP, if someone is on some Kurenai brainlet vibes and tries genjutsu on an uchiha you can hit them with the old "no u" and flip it right back on them, you could even layer the flip if you have the right specialities making a nasty combo.
Phosphorescent light isn't particularly "good" and I don't really like it that much, however it is fast and again any genjutsu can be useful with the right layering even something as simple as this. For example I could layer it with my own soft body genjutsu to prevent them from escaping the explosions.
Dusk Crow is handy in that it doesn't require eye contact and I believe causes paralysation? The description somewhat implies you are immobile and I believe it's based on the illusion Itachi used on Naruto which did leave his immobile and off the floor in the illusion.
Ah Ephemeral the old finger genjutsu itself, I actually have a cool combo I could use with this, turning the friend in to a pseudo CoT with my blackened mirror tech. It's cool because I mean you can point a finger to trigger it, all the no eye contact gen are useful for that though honestly.
Paralyzing Fear is one of the better Sharingan genjutsu honestly, it allows you to inflict immediate paralysis nearly, with very little wind up time. By the time the person realises they're in a gen they're usually paralysed making this an easier gen to follow up from, also no handseals paralytic techniques are always nasty.
Sword Hell is a new one I think, or at least I never paid it much attention before if it's old. I like the aesthetic of it, bootleg Tsukuyomi vibes. The range is kinda lame however, but there are as always ways around that.
Bound by Soul Technique is basically good for the same reasons as paralysing fear, it's very fast causes paralysis and allows easy follow up, just don't try it on any Jinchuriki otherwise you're liable to get absolutely ratio'd with a lariat.
Alright now on to the eye contact required genjutsu. First up we have Copy Wheel Eye Illusion. The best 3T illusion IF you can force eye contact, it allows freely created genjutsu, essentially freeform if you like. The possibilities for this are almost endless provided you can actually use it, but there are some tricks to forcing eye contact that I'm aware of.
Burning Paper Body is kinda bad, I mean it's worse than paralyzing fear, it's also worse than bound by soul, I truly don't think I'd ever use this unless it was solely for the aesthetic of setting someone on fire, maybe you could cover it being an illusion if you'd actually used a lot of fire before hand but that would require RPers to play along, X to doubt.
Piercing Feathers is a sleeper genjutsu when it comes to quality, while it says it's a weaker shackling stakes, which it is by rank at least. It actually has long range capabilities making it very potent if someone forgets to avoid eye contact. So it can work as a tricky manouver in some circumstance.
Shackling Stakes is a very aesthetic move it works in short range only though sadly, this coupled with it's rank makes it inferior to the generic sharingan illusion technique in a lot of regards, this could be fun to use but overall it's just a weaker version of the generic technique, it really needs it's range increased honestly if it was meant to be viable.