AMMDI is an open-notebook hypertext writing experiment, authored by Mike Travers aka mtraven. It's a work in progress and some parts are more polished than others. Comments welcome! More.
You're right that "panrealism" seems like it should be a term - it's a very logical construction! The closest established philosophical position would be ontological liberalism (also called ontological permissivism). This is the view that existence is "cheap" and that our ontology should be quite inclusive rather than restrictive.
Ontological liberals argue that we should generally accept that things exist rather than being skeptical about their existence. Philosopher Amie Thomasson has been a prominent defender of this kind of view. The basic idea is that if we have conceptual schemes that seem to refer to certain kinds of things (numbers, fictional characters, social institutions, etc.), we should generally accept that those things exist in the relevant sense rather than trying to eliminate them from our ontology.
Other somewhat related positions include:
Meinongianism - the view that there are objects that have "being" even if they don't "exist" (so in some sense, more things are real than we might think)
Ontological maximalism - though this term is less established in the literature
You're absolutely right that eliminativism represents the opposite impulse - trying to show that things we think exist (like beliefs, consciousness, moral facts, etc.) should be eliminated from our best theory of what's real.
It's interesting that "panrealism" hasn't caught on as a term, since it would be a neat way to capture the maximally inclusive ontological stance. The philosophical community can be somewhat conservative about terminology, but there's nothing stopping the term from gaining traction if it proves useful!