Here are some ideas for small group (or personal) study on the Psalms.
33 (over everything)
2 (through the Messiah)
Why does evil flourish?
49 (or 10; simply reading one out loud, well, and looking in depth at the other works well. Sometimes we just need to listen to the Word.)
73 (a particularly good response to this problem)
26 (note the 'problem' of the Psalmist saying he's totally righteous - how does that work?)
When God is far or near
42 & 43 (they're probably one psalm)
Persecution and enemies
56 (there's a nice ABCBA' pattern in this psalm; 1-2, 3-4, 5-9a, 9b-11, 12-13)
145 (carefully explore the reasons in the text, and remember similar in your own life)