Salesforce recently introduced new Field Type named Time, it can be used to keep track of time which are not specific to date. Like daily call time.
Along with the new Field Type we even get functions to support the Time field type in Formula fields
TIMEVALUE – Returns Time
TIMENOW – Current Time
HOUR – Returns the Hour of the day
MINUTE – Returns the Minute of the day
SECOND – Returns the Secend of the day
MILLISECOND – Returns the MILLISECOND of the day