Some of the tools i'm using in day-to-day development - Residing in ~/bin, along with some installations, as follows:

General Tools

colcount - Converts standard input lines to their respective column counts
q - See https://github.com/harelba/q
secs2date - Converts timestamps to human date-time strings
sigma - Sums up all the numbers from stdin
xvsy - Draws an XY graph of x values vs y values - Getting pairs of x,y lines from standard input
categoryvsy - Draws a bar graph for category names vs y values - Getting pairs of category-name,y lines from standard input
display - Uses disper in order to control multiple monitor setups for the same machine (docked, undocked,home etc.)
disable-company-settings/enable-company-settings - Allow quick switching between a company provided maven settings.xml and a default one
svn-diff-meld - Wrapper so svn would work with meld
mvn-test-multiple - Run a test using maven multiple times, each time saving the log file and the test results to separate files
groupby - Count lines per distinct data value in column number colnumber.
hive-table-fields-to-pig-load-command - Converts the output of a hive DESCRIBE command into a Pig LOAD command

Zookeeper related utilities:

zkfind - get a zookeeper path and lists all nodes recursively, similar to linux find
zkget - gets the data of a specific node in zookeeper
zkrmr - Performs a recusrive delete of zookeeper nodes (this capability is included in zkCli if you're using zookeeper >3.4)
zkgrep - Finds a substring in the data of zookeeper nodes