It is not easy to make a 7x7 palindromic square with common words as nouns, adjectives, verbs, etc. In Serbia, puzzlers have made 10-15 such squares, all with some unusual terms like the title of a book, or the name of a person or geographical place. With the help of atlases and the Internet, we can make even some thematic palindrome squares. Most of these interesting places I found on the Dan Tilque site.
"620 7x7 Squares WIth Geographical Palindromes,"
Word Ways: Vol. 38
, Article 5.
Available at: http://digitalcommons.butler.edu/wordways/vol38/iss3/5