The keywords for Sakura's Pokemon are "healing" and "pink", usually both where possible, though yes I tried to match them to specific Naruto characters in Sakura's life as well. I may have other Trainers' Pokemon being reminiscent of the Naruto characters I don't include on her team, though.
Alright. Healing + Pink + Johto Region
Gonna spit out some guesses.
Major Guesses
Miltank - Milk Drink provides healing both for self and others.
Hoppip/Shiny Jumpluff - Synthesis, Ingrain, Leech Seed, Pollen Puff, Mega/Giga Drain, Grassy Terrain, Strength Sap. Huge amount of healing potential both for itself and for allies.
Slowpoke line - Can learn Heal Pulse and also Slack Off, can have the ability Regenerator.
Clefairy lines- Heal Pulse, Life Dew, Healing Wish,
Corsola - Recover, Life Dew, Aqua Ring, and the abilities Regenerator or Natural Cure
Weaker possibilities
Chansey line - I feel if Sakura really wanted one, she could easily get one from the Joy clan.
Jigglypuff line - Basically almost the same as Clefairy line, but in general has less healing moves available to it. It is conceivably less rare than Clefairy however, so it could easily be the Pokemon Sakura can locate.
Joke guesses
Mew - Can learn literally every healing move.
Shiny Celebi - Healing via time-travel shenanigans.
Of these guesses, Miltank is the only Pokemon where I can draw a pretty clear reference to a Naruto character, that being Tsunade. The combination of the super strength and the massive...erhem...womanly assets would absolutely a parallel to Tsunade.