Magikoopa: Waves his wand around and something random happens (Giant transformation, flower damage, lava floor, etc.)
I like this.
Some Kirby Assist Trophies because why not.
Bandana Waddle Dee: He sticks around the summoner in a similar way as how Popo/Nana fight together as the Ice Climbers. While he usually stays behind, the long spear can reach the enemies in front of the summoner, so you can do combined attacks with him, the spear will stun the enemies while you can charge a full Smash attack and punish them.
He has a small moveset of 4 attacks: an upward stab, a front stab, a fast multiple front stabs combo which lasts for a couple of seconds and can stun the enemies, and a stomp move. In addition to this, when the player ran out of jumps and presses the jump button again, he teleports over the player and is automatically grabbed: he will lift the player around with the "spear copter" for a limited time: that's an additional recovery move that can be used instead of up-b, and the rotating spear can deal some damage.
Can be defeated.
Adeleine: She draws on a canvas in a layer away from the stage's plane. Basically she's similar to Vince, but more advanced. She has 50% chance to draw an item from a pool (usually maxim tomato, but she can also draw other stuff such as a great amount of food, bob ombs, hammer, etc... even a Final Smash Ball if they are set on; usually she draws powerful items anyway), and a 50% chance of drawing a boss, it depends on if she's happy or angry when you summon her.
The bosses she can summon are the usual Kracko or Ice Dragon... depending on how much effort they want to put into developing the assist trophy, maybe you can add in a few more bosses such as Dark Matter, Sweet Stuff, Mr Shine & Mr Bright or Waiu (maybe some new ones too). All the bosses have a very simple attack pattern and can be defeated. If the boss is defeated, Adeleine will jump into the main layer of the stage and will rush into the player who defeated the boss with her signature flail move. In this state she can be defeated with 1 hit, and if she hits you she's still automatically defeated, though in that case you will get the damage and knockback too.
Rick, Kine and Coo: They jump around the stage, target a random opponent and attack them. Rick will shoot fire from his mouth, Kine will just position himself into the player and splash some water to stun them, and Coo will fly around the target and shoot some cutting feathers. They can't be defeated, but their attack is simple and predictable, you just need to dodge them.
They appear all at once, though one animal can target only one player at time. If there is only one opponent, he will be attacked by only one of the three animals, while the others will just jump, fly and move around the stage. Once the attack is finished, another attack can begin, though the same animal can't target the same player more than once per summon.
If you are too far from an animal, that animal will ignore you (they have a limited range for targeting players).
Computer Virus: It's a bunch of computer windows of several dimensions. There is a main window with the picture of the enemy: it's a retro styled generic RPG enemy that's different every time you summon it; the secondary windows contain a dialogue box and the statistics, including the HP value of the enemy.
It's a turn based fight. When the enemy attacks, it can't be damaged. The attacks do affect the whole screen and are stuff such as, a shooting stars rain, a strong wind with some cutting shockwaves here and there, a wave of fire, etc.
After each attack, it's the players' turn: the enemy comes out from the window and lands on the stage, standing still. You can hit it and decrease its amount of HP until it reaches 0.
When the enemy is defeated, the dialogue box will show all the points gained (including the joke ones such as big smile points, happiness points, etc.), and the defeated enemy will drop some items: one equippable item (a weapon or a power up) and some food of amount depending on how strong the enemy was.
Gigant Edge: The huge knight mid-boss from Kirby's Return to Dream Land, but more based off the version that appears in the Kirby Clash series.
Basically it does the same attack pattern as in the Clash games, and can be defeated if you manage to consume its HP value (though it's not visible).
When it gets enough damage, it starts flashing red, faster and darker the closer it is from being defeated.
Occasionally, but it's very rare, can spawn as the fire variant from Super Kirby Clash instead of its base neutral form.
Ribbon: She can spawn only if Kirby is in the battle. She flies to where Kirby is, kisses him, and then he blushes and starts walking backwards like a drunk until he falls off the stage. Until Kirby loses his stock, he can't be controlled anymore. Ribbon can turn against the summoner if the summoner plays as Kirby.
(ok this one is a joke)
There are countless options, I just ran out of ideas for now.
