Things like 
's Hawkshot, 
and 
grant vision on enemies. Can the enemy see the animations / effects too?
I'm guessing yes.
Are there any enemy reveal skills that do not tell the enemy that you can see them (besides 
and 
)?
Edit: Reworded some things to make it clearer
Raise Dongrs1 votesThe enemy can see the spell/item being used, but they do not gain vision from it
Ariaflux1 votesOh that's what I was thinking (I didn't mean enemies actually getting vision, I worded that badly).
So there are no skills / items that reveal enemies without making them aware of it?
Anyway, thanks for the answer!
Raise Dongrs1 votesAlso if you're not in the bush that's being warded, you do see a gust of air from the ward an enemy is placing
Centuros1 votesQuinn says something and there is an expanding circle when she uses her vision that makes it very obvious, but I don't think you can see this if she's in the fog of war. Also, the enemy team cannot see Rek'Sai's sonar.
You can, however, see the exploding hawk and a reveal circle for those listed in your post, even when you cannot see the champions that used them.
Ariaflux1 votesI see, I'll try to test Quinn if possible.
Btw, on Hawkshot, can the enemy see the trail before it burst, or just the burst location?
Risk of Fate1 votesThey can see the trail and burst.
Ariaflux1 votesI see, thanks!
Captain Aishi1 votesrengar ult, he gains vision of enemies from further than they get a ! sign that he's in leap range
Ariaflux1 votesOh interesting o.o
Thanks!
Drunk Rummate1 voteswith the scrying orb you will see a little icon appear over the enemy's head granting you vision. they can also see that, and they see the scrying orb circle as well (so they know what you did and didnt see)
they can see the visual for hawkshot and the glitter it leaves behind as well. they don't see the exact area that it covers though.
Ariaflux1 votesGot it, thanks!
zliplus1 votesAs the other examples indicate, it works on a case-by-case basis. For example, Twitch ambushes are very dangerous because you can only see him going into stealth and he can travel a far distance in it. Abilities that specifically reveal a champion hit will usually show as a debuff though.