Filler Puzzle

Start by trying to identify as many images as you can. Pretty much all of the resulting words have something in common, which you might be able to get by googling some of the unusual ones together or just by asking other teammates.

The relevant commonality is that almost all of the words are examples of crosswordese.

It is very relevant that almost all of the words are crosswordese. For the next step, it may be useful to think about why the images are divided into two groups.

Try reading the first letters of the first several words in the second group. Do you see anything?

This is a diagramless crossword, where the images in the first half are across clues and the images in the second half are down clues. The crossword obeys standard conventions like 180-degree rotational symmetry and every entry being at least 3 letters long.

[If solvers are stuck on the crossword, confirm which clues they have right and maybe provide some of the harder ones like RPI or EGEST]

There is one unclued entry in the crossword. That is your answer.