The perfect Russian verbs refer to those actions that are complete, or of a single nature. For example- 'I wrote a letter (on completion)' is a perfect action, while 'I wrote a letter' is an imperfect action, because it does not denote completing the action.
This page lists the most important perfect verbs. The table describes the phonetics, as well as the required conjugation pattern (This is indicated by the number 1 or 2). Remember that perfect verbs can not be used in the present.