There are 15 statistics on Gelfand-Tsetlin patterns in the database:
(and possibly some waiting for verification)

St000072Gelfand-Tsetlin patterns ⟶ ℤ
The number of circled entries.
St000073Gelfand-Tsetlin patterns ⟶ ℤ
The number of boxed entries.
St000074Gelfand-Tsetlin patterns ⟶ ℤ
The number of special entries.
St000077Gelfand-Tsetlin patterns ⟶ ℤ
The number of boxed and circled entries.
St000114Gelfand-Tsetlin patterns ⟶ ℤ
The sum of the entries of the Gelfand-Tsetlin pattern.
St000115Gelfand-Tsetlin patterns ⟶ ℤ
The single entry in the last row.
St000152Gelfand-Tsetlin patterns ⟶ ℤ
The number of boxed plus the number of special entries.
St000176Gelfand-Tsetlin patterns ⟶ ℤ
The total number of tiles in the Gelfand-Tsetlin pattern.
St000177Gelfand-Tsetlin patterns ⟶ ℤ
The number of free tiles in the pattern.
St000178Gelfand-Tsetlin patterns ⟶ ℤ
Number of free entries.
St000186Gelfand-Tsetlin patterns ⟶ ℤ
The sum of the first row in a Gelfand-Tsetlin pattern.
St001404Gelfand-Tsetlin patterns ⟶ ℤ
The number of distinct entries in a Gelfand Tsetlin pattern.
St001406Gelfand-Tsetlin patterns ⟶ ℤ
The number of nonzero entries in a Gelfand Tsetlin pattern.
St001686Gelfand-Tsetlin patterns ⟶ ℤ
The order of promotion on a Gelfand-Tsetlin pattern.
St001713Gelfand-Tsetlin patterns ⟶ ℤ
The difference of the first and last value in the first row of the Gelfand-Tsetlin pattern.