Old Pokémon you have?
I did play Pokémon a lot as a little kid but the save files I had were always finished, so the first mon I remember getting by myself was a Litten when I learnt how to reset and resetted a finished copy of Pokémon Sun and Moon I got recently at the time.
I unfortunately lost the cartridge a few years ago, along with a lot of my older Pokémon but my other games like X have some kinda old Pokémon. I unfortunately could barely find any Pokémon from 2016 and before, and a lot don't have a nickname or story. Most of the Pokémon before that got lost to resets and me being stupid until I remembered trading exists.
A midnight Lycanroc from 2018 named 'Hardtocatch' for obvious reasons
A Ditto from "2011" (I messed with time often) just named 'BRO'
A Noctowl from the same year, also named 'BRO'
My first shiny, a now Gengar named "haunter.." from "2014"
A Lapras from 2019 named 'Latias'
A Zorua from 2017 named 'Zoro' (I caught a lot around that time thanks to ORAS's PokéNav and named them all things that sound like Zorua)
A Rhyhorn from 2018 named 'Rhyno'
Countless Pokémon from different times whose name ends in or contains -, or multiple -, for no reason
A Sewaddle from 2019 named '1stafterleg' (First after League) because it was the first I caught in the post game
The Steelix from an ingame trade in XY, level 90 and from 2016
And that's it until I feel like checking more of my old save files, this took a while to make even though I've ignored a ton of Pokémon here.