Too many to mention them all - but a few examples are:

Gardens:

Eden project

Lost Gardens of Heligan

Caerhayes Castle and Gardens

Pinetum Gardens

 

National Trust/English Heritage/Stately Homes

Lanhydrock

Cotehele

Tintagel Castle

Tintagel Post Office

Pencarrow

Prideaux Place

Restormel Castle

St Catherine's Castle

 

Other attractions:

Camel Trail

Rough Tor/Brown Willy/Cheesewring

Bodmin Jail

Bodmin Courtroom Experience

Museum of Witchcraft, Boscastle

Arthurian Centre, Tintagel

Bodmin and Wenford Railway

Segway Bude

The National Lobster Hatchery

Shipwreck Centre, Charlestown

Wheal Martyn Clay Works

St Austell Brewery Visitors Centre

Tintagel Brewery Visitor Centre

Camel Valley Vineyard