Other Combat Technologies
While mobile weapons and battleships are far and away the most common gear of the era, a variety of secondary technologies get employed in warfare as well. Below are some of the most common types.
The classics never die! Conventional pre-Overtechnology weaponry is still in use. Helicopters and planes with helicopter characteristics are still popular as support craft, though nations with strong mobile weapon contingents tend to buy armed sub-flight systems instead for the same purpose, since these can be used either as manned support craft or unmanned ways to get MS that don't belong in the air in the air. Tanks also remain reasonably popular on Earth, due to being radically cheaper than whatever the latest Guntank-derived nightmare that serves no practical purpose is.
Emplaced guns are tremendously popular on Earth for civil defense, in part because they're so easy to get. Pretty much any mobile weapon or battleship has a cannon or missile launcher from its original loadout in service as an emplacement somewhere or another, though wealthier Federation nations take the time to dress these up a little.
While these generally underperform against mobile weapons, they often see use as a way to funnel mobile weapon engagements into a terrain the defender finds favorable.
The term "mobile armor" is essentially meaningless at this point, because spacenoids and Earthnoids do not... precisely... agree on the definition.
To an Earthnoid, "mobile armor" generally connotes military hardware that is not a tank, IFV, or atmospheric-use aircraft that does not have a humanoid shape. This definition comes from the notion of "armor" as the catch-all term for mechanized infantry, tank corps, and their gear; "mobile" armor, thus, is armor that is not traditional conventional arms. Any number of limbs is fine, though generally something with four limbs will instead be a mobile suit. It sometimes includes pre-Overtechnology design paradigms.
To a spacenoid, "mobile armor" generally connotes military hardware with fewer than four limbs, regardless of its intended location of use, specifically designed to take on a "battleship-like" role without a battleship-like crew complement. This comes specifically from the need to distinguish this class of weapon from the mobile suit. It pointedly does not include pre-Overtechnology design paradigms like tanks and planes (in part because these are so niche to spacenoid engineers that the idea of bothering with a term for them in modern warfare is absurd on its face).
These definitions are both blurry and have a certain amount of crosstalk with one another after decades of development. The question of whether this includes planes and air/space superiority fighters is an open one; it is currently in vogue to refer to nontransformable, nondeformable air/space fighters as mobile armor, within the Federation, but elsewhere doing so mostly causes headaches.
Everyone is always trying to put their own spin on mobile weapons. Always. REA China has the Gun-Ru, a non-MULS-P compliant KMF derivative with chunky limbs and a very stable third landspinner limb; the AEU has been trying to get the balance between plane, VF, and mobile suit just right for decades; one could argue some of the Federation's early mobile suits, such as the Guntank, also qualify as pseudo-mobile weapons.
As with mobile armor, this is a murky category. Both of these categories primarily exist for engineering hiring managers to assess whether an engineer has the same definition of the term.