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No record, but one of the more silly challenges might be to only use rental Pokémon from stadium in regular OU. Maybe just move sets or potentially DVs and stat experience though those might be too much of a nerf. Chansey would need a modification as it runs minimize in rentals.
RBYLT accounts can be used for ladder achievements! If you get a good enough elo/GXE/winstreak with your RBYLT account you can use it to get a ladder achievement!