classic plants that were brought to europe include some important food plants:
-tomato (this also has a lot of texture to touch and a strong smell), potato, corn, -chiles (these have some dramatic sensory effects!)
-tagetes (marigolds) are another import with texture and fragrance..
-opuntias and agaves are very widely grown and naturalised in southern europe, and are
not old world natives--lots of texture there too!
-dahlias, zinnias
i know i've mixed up your two categories
grasses/grains have a range of visual tactile and even auditory (wind in a field of dry mature grain or grass) effects through the year-bright green soft yet sharp shoots (that you can make a whistle out of) developing feathery flower heads, and growing into dry tough papery mature stalks with hard seeds--and people chew grass stalks and seeds at all stages ....caution needed if people are being encouraged to touch as grass can cut..
herbs are (maybe too) obvious choices..
there are some wonderful plectranthus species ('cuban oregano' 'piss off plant' ;etc nothing like origanum) which are mostly(all?) tender, but have soft fat furry leaves with pungent menthol like scents, can be grown as bedding plants..
