Idek if this is possible, but you could ask the FS Buddy's creator to add a smash ball item.
Just saying

make a rare chance for there to be a Tamat?Mojibaka item that just crashes the game when you try to use it.

Literally any item from the smash bros series.

something similar to pokeballs but it isn't throwable and it summons a creature of aether character to perform some attacks and then leave.

Attack Booster: Increases the power of the next attack you use for the rest of the stock.

maybe a stun grenade that hits any player in the radius with clairen tipper?

Some Item Ideas

1.An Item that Makes the player Floaty. This would work well with the feather item.
2.An item that puts an Aura around the player Which gives the opposing player full poison if they walk into it.
3.An item that puts the opposing player in a Ranno Bubble
4.An item that gives the player's Attacks more hitstun
5.An item that Clones the player
6.An item that gives the player Invincibility for 10s
7.An item that makes the player take half damage
8.An Item that gives you a movement speed up. Maybe Like a Pair of boots
9.An item that gives you Turbo Mode for like 10s
10. A Boomerang
11. An item similar to the Ender Pearl, it teleports you to the enemy
12.An item that blows a gust of wind. Maybe it could have synergy with the Trap item by blowing it around

More Ideas

1. Mega Mushroom
2. Tiny Mushroom
3. An item that turns the player Invisible
4. An item that makes the player heavy (Metal Box)
5. A Portal item
6. A gun that laser Beam\ Wave
7. An item that makes the player invisible
8. An that swaps player positions
9. An item that continuously heals the player when being held

Creature Ideas

1. A creature that Brings the player a item that is on a the stage
2. A creature that slows down opposing players in proximity
3. A creature that makes a force field that projectiles cant go in (Clairen Dspecial)
4. A creature that latches on to players
5. A Creature that teleports the opposing player to random parts of the map (Abra)
6. A Spiky Creature that walks around the map and hurts any Players that touch it

I feel like a smoke bomb that releases fields of smoke (like those from forsburn) would be cool

How about a creature that runs around on the ground until it reaches an opponent and punches them in the gut really hard so that they stay on the ground helpless for a moment
(Simplified: punches opponent = grounded freefall)

if not added yet, invincibility star/lollipop. makes you invincible for around 10-20 sec.

my other idea is a item*