Bulbasaur line
Oddish line
Paras line
Bellsprout
Exeggcute
Tangela line
Chikorita line
Hoppip line
Sunkern line
Celebi
Treecko line
Lotad line
Seedot line
Shroomish line
Cacnea line
Tropius
Turtwig line
Budew line
Cherubi line
Carnivine
Snover line
Shaymin
Pansage line
Cottonee line
Petilil line
Maractus
Foongus line
Ferroseed line
Chespin line
Phantump line
Pumpkaboo line
Fomantis line
Morelull line
Bounsweet line
Dhelmise
Gossifleur line
Applin line
Zarude
Farfetch'd, Galarian Farfetch'd, and Sirfetch'd hold leeks*
Regigigas has moss on it*
The Flabébé line attaches itself to flowers
Pancham and Pangoro use leaves in battle and hold them in their mouths*
Skrelp and Dragalge are based on kelp
Comfey has a flower lei
Oranguru has a leaf fan*
Komala has a log*
Celesteela is partially based off bamboo
Kartana is origami, which comes from paper, which comes from trees*
Hope I helped!
*= debatable. They interact with plants in some way, but are not exactly based on plants.
