Angus: See
Dundee: other attractions include McManus Gallery, Desperate Dan, the Science Centre, and the University Botanic Garden.
Pictish stones have striking designs, often a "Z-rod" with discs. The best examples can be seen at Aberlemno (on B9134 midway between Forfar and Brechin), but these (and many other outdoor stones) are boxed in winter to prevent frost damage. Museum collections can be seen at Forfar, Meigle, Montrose, Brechin, St Vigeans just north of Arbroath, Dundee, and the National Museum in Edinburgh.
Castles: Glamis near Forfar is the big draw, but Edzell near Brechin is a gem with its walled garden. Lots more turrets and tumbledown ruins, such as Broughty Ferry.
A pre-World War I airbase defends Montrose.
Scotland's Gardens opens up private gardens once a year in summer, with all proceeds going to charity. There are about 30 participating gardens in this area, dates staggered so there's one open most weekends.