[2022] What are some mechanics of a champ that not many people know about?

These are probably not that obscure but they're fun to play with:

• You can hide Renata Glascs's Q animation in her E; E and immediately Qing will make her Q animation harder to see.
• You can use Flash to redirect Renata Glasc's ultimate by executing ult and immediately pressing Flash. This can also be done with other champions with cast times on their abilities, such as Qiyanas ult, Pyke's Q or Gragas E (a more well known example). This is useful for hitting someone over a wall with very little reaction time.
• Pykes E stun occurs when the shadow passes through a target. You can use Pyke's ultimate and Flash to redirect the shadow by repositioning yourself with those abilities. These can also be chained by using Pyke E, Flash and R with precise timing to redirect the ability multiple times.
• Orianna's ball range is larger than her Q and E ranges. You can use this to keep the ball in a particular location to zone even if you move out of range to use your abilities. When the ball is out of Q range but still within leash range, you can use Q to move the ball if youre in range of the destination, even if the origin of the ball is out of range. This can be used to harass an out of range opponent, particularly one moving toward you.
• At any point during the dash of Akali's E, you can cast other abilities.
• Anivia's Q has two instances of damage: Once it passes over the target, and once when it explodes or is detonated. Many new Anivia players will only hit the detonation damage. You can use this to proc spellshields and still land a stun. And, as mentioned elsewhere, Anivia's R does damage when it's re-activated so you can use it to last hit.
• You can improve your winrate when playing Ryze by not picking him if your name is Riot Dan Honks.

I'm basing this off of "I havent played Akali outside of ARAM in a few months" so you might be right