Tengwar likely has to wait for the JRR Tolkien estate to release it to the public domain (CC0, for instance) or for the copyrights to expire on their own in a century or so.

(Same with Klingon glyphs and others.)

Such uses are probably fair use, but the Unicode consortium seems hesitant to test "probably" versus reality, especially since they would not see the brunt of the consequences but font authors and others might.