Lexar cards are recommended by Fujifilm and the cards I use in my cameras. The Lexar Professional 2000x cards are great, but the 1667x and 1066x cards are also very good. Outside of the X-T4, you can use most cards on sale without the card holding you back, but if you have an X-T4 I highly recommend getting 2000x cards. you can find the full sale here on Amazon.