There are 5 kind of psalms: praise, wisdom, royal, thankgiving, lament. There are 4 kinds of prayer: adoration, contrition, thankgiving, supplication....

Wow, those
are detailed questions and answers.  I think that you need to remember that you will choose the
psalms and prayer based on the occasion.  There are this many so that you will be able to find
the one you need based on when you need it.