Sort:  

fourth one from the left it is theta because name of all the others end with an i

Congratulations! Finally... Theta is writted complete different to xi, chi, psi, pi and phi.

Thank you so much I already got 3 Steem :)
The best part about your puzzles is unlike others they are not googlable :P

;) hehehehe I know, the reason of the images... and I always change something... you are welcome and congratulations again!