If you want the best idea, just look at the last paragraph and ignore everything else.
Entirely too many to write about here in entirety, but I'll write a few that I remember ATM:
A setup, so multiple devices, of: a ~~feature~~ phone based on flipper zero with buttons on it like it's a fidget toy (but actually functional) and a foldable tablet that looks like a notebook (Lenovo yoga fold)
A tablet based off of Pixel C, MacBook, ROG Flow Z13 and/or Pixelbook with magnets in the body to stick it anywhere like Google tablets usually have, the look and keyboard of Pixelbook (it's just a personal favourite), trackpad and SoC from Macs, gaming capabilities from windows, and a screen with the new 3D tech (for designing 3D prints), microLED, and 240 Hz+ VRR
A controller based on a combination of dualsense, xbox elite, and steam controller with a low energy display doubling as a trackpad in the middle
Screen tech which is capable of giving actual tactile feel of buttons so I can have double screen or foldable device without sacrificing on a keyboard good for touch typing.
A mixed reality headset as small as sunglasses with capabilities of the best of them
A headset which I can stick around my ear and get audio directly into my nerves with very little if any invasive surgery
Basically Nokia morph concept but in real life would also be really cool
While typing about magnets I remembered the actual thing I really want to exist currently: polymagnet based devices and accessories. It can be so futuristic if implemented properly, and a game changer, though I assume it's not mass production ready yet or someone would have applied it. Everything else is just my imagination running wild, not that I consider this a reasonable thing either.