According to a sugyah in the Talmud Yerushalmi there were rabbis who held the opinion you should recite a beracha when taking off tefillin:
כשהוא חולצן מהו אומר ברוך אשר קדשנו במצותיו וצונו לשמור חוקיו. ואתיא כמאן דמר בחוקת תפילין הכתוב מדבר ברם כמאן דמר בחוקת הפסח הכתוב מדבר לא בדא.
When he takes them off, what does he say? “Praised Who sanctified us by His commandments and commanded us to obey His laws.” That follows the opinion that the verse speaks about the law of tefillin. However, according to those who say that the verse speaks about the law of Passover, that does not apply.
Why nowadays do almost no Jews practice that, with the only exception I know being rabbi David Bar Hayim?