This list of all two-letter combinations includes 1352 (2 × 26 2) of the possible 2704 (52 2) combinations of upper and lower case from the modern core Latin alphabet.A two-letter combination in bold means that the link links straight to a Wikipedia article (not a disambiguation page).. H u n t s v i l l e H o s p i t a l H e a l t h S y s t e m.. Agents is a fictional team of superheroes that appeared in comic books originally published by Tower Comics in the 1960s..