True Fana and Sacrifice of Form are both sweet cards letting a Wizard obliterate an attack against them. I've always wondered what "True Fana" meant. I hadn't seen the term in The Lord of the Rings or the Silmarillion. I just assumed it meant "True/Final Form" given the ability and the artwork of Gandalf smoting the bridge with his staff to drop the Balrog into the abyss. Sacrifice of Form has a similar ability and the title seems to refer to Gandalf's sacrifice in stopping the Balrog, but the artwork doesn't depict that scene. Perhaps the artwork is "old man" Gandalf in Fangorn after his return. It turns out these (obvious?) assumptions are correct but the background of these card titles are pretty interesting.
"Fana" is a Quenya word (the language of the High Elves in Valinor). It literally means "white cloud." It has a secondary meaning of "veil," like a veil of fog. Leaving "fana" for a minute, most MECCG players will know from the introduction that the wizards are Maiar (divine beings similar but lesser to the Valar) sent to Middle-Earth to help the free peoples in their fight against Sauron. Unlike other Maiar and the Valar, the Wizards are "incarnate." Meaning, they take the form of humans and are subject to weariness, pain, and death while only retaining some of their Maiar powers. Other (non-incarnate) maiar do not appear in The Lord of the Rings. But in the Silmarillion the Valar and Maiar would sometimes interact with Elves and Men, taking visible form referred to as "raiment," which could be changed at will. This raiment acts as a "veil" over the Maiar's true form and so the elves referred to it as "Fana." And so the card "True Fana" seems to refer to a Maiar's ability to remove their raiment and reveal their true form. Right on! (except Gandalf is incarnate and can't do this).
As for "Sacrifice of Form," the term "sacrifice" is not used in The Lord of the Rings. Still, it seems clear that this is referring to Gandalf's sacrifice of his incarnate self. But what is the origin of the title of the card? Well, Tolkien had this to say about Gandalf in one of his private letters:
They thus appears as 'old' sage figures. But... all the 'angelic' powers concerned with this world were capable of many degrees of error... The wizards were not exempt, indeed being incarnate were more likely to stray, or err. Gandalf alone fully passes the test, on a moral plane anyway (he makes mistakes of judgment). For in his condition it was for him a sacrifice to perish on the Bridge in defense of his companions, less perhaps than for a motal Man or Hobbit, since he had a far greater inner power than they; but also, more, since it was a humbling and abnegation of himself in conformity to 'the Rules': for all he could know at that moment he was the only person who could direct the resistance to Sauron successfully, and all his mission was vain. He was handing over to the Authority that ordained the Rules, and giving up personal hope of success.
So, it appears that Coleman read Tolkien's letter as well as Parma Eldalamberon.