There's a trick to identify these... thanks Olrox ! Anyhow, many of them are hard coded in the client.
15 Soul Strike pok1.tga pok3.tga ring_blue.tga lens1.tga lens2.tga
17 Magnum Break ring_yellow.tga ´ëÆø¹ß.tga
27 Frost Diver (Traveling to Target) ice.tga pok1.tga pok3.tga smoke.tga
28 Frost Diver (Hitting) pok1.tga pok3.tga smoke.tga
226 Grand Cross Effect alpha_center.tga ring_white.tga ring_yellow.tga
252 Reflect Shield ring_yellow.tga
312 Heal Effect ring_white.tga pok1.tga pok3.tga
336 Kyrie Eleison/Parrying Shield kyrie.str
409 Meteor Assault purpleslash.tga
Edit : You can view the resources of STR files using GRF Editor, ex :