grammar - Particle に to enumerate things?

I encountered several sentences where に was used—from my deduction of the context—to enumerate things. For example a character about to go somewhere, checks his bag if he has everything he needs :
2:「忘れ物は？」
1:「大丈夫ー」
1:「－だと思うけど確認しておこう」
1:「バンデージにタオルに」
1:「トランクス」

I tried searching this grammar but couldn't satisfy my curiosity. Why and how に is used to enumerate things? I understand that it is basically used to tell the time, place, directions, cause, ect... But I'm lost on how to understand it used in that way.

Answer

The parallel marker に is used when you're putting together a list of related things (nouns), adding each one as you go. In particular, it gets used if you're trying to think of things (like when you're at a restaurant, trying to think of what food you want to get), and that includes when you're trying to recall at least two things from memory (like if you're trying to remember the names of a couple old friends).

I'm not a native speaker, so I won't try to make up my own examples. I'll take a couple from the 日本語文法ハンドブック:

大根ににんじんに、えーと、それからトマトをもらおうかしら。

In this example, the speaker is trying to think of which food they'd like. They list three: 大根, にんじん, and トマト. Note that the last item doesn't have に. Also pay attention to the えーと、それから which helps give you the impression that the speaker is trying to think of the items--that's the sort of situation in which you tend to run across に.

Let's look at another example:

イタリア旅行ではいろんな都市を訪ねたわ。ローマにフィレンツェでしょ、それからミラノにヴェネツィアも行ったかしら。

Here again, the speaker is trying to call to mind a list of items. In this case, there are two smaller lists, but they function as one larger list: ローマ and フィレンツェ form the first list, and then the speaker thinks of ミラノ and ヴェネツィア as well, adding them as a second list. In each case, に is left off the end of the list.

Another example, this time from a video game (Gameboy Wars Advance 2):

「ほっほっほっ。マックスにイワン。
また、ともに戦う事になってしもうたのう。」

The speaker remembers Max and Ewan from the first game, but he hasn't seen them in quite some time. Because he used に to list the names, you get the sense that he's calling their names to mind from memory. In this case, again the list only has two items, and again に is omitted from the last item in the list.