The photo here is from "MuseScore", the free notation software. A note head replaces a note head, shown in this photo.
Since I have never seen these note heads before, what are these used for (if ever used) and where? I see some common ones, like the first and 13th one, but the ladder and the other I do not know. Thank you~
Some of it appears to be a variation of shape notes (5,8,9,10,11,12), others seem based on larger note values that are quite rare in modern music and clef like (6,14). Some (mainly the Xs and triangles) seem based on percussion notation (2,7,8) and some just seem to be decorations (1,3,4,13).
As these notes heads come from different places and are used in different situations it's best not to use them until you learn more about them.
Here are some of example of where alternate note heads are useful. There are probably more that I can't think of, or am unaware of.
The "ladder" shape is one form of the double-whole note (aka breve). As you might expect, it has twice the duration of a regular whole note.
Notation for percussion instruments oftens use various shapes to indicate different drums (such as an 'x' for high-hat), or different types of drum strikes.
Similarly, spoken parts that are unpitched, but require being notated in the score (usually for rhythmic reasons) will also use an 'x'-shaped note head.
There is a notational tradition among some singers to use shaped notes to indicate scale degree (basically a notated version of solfege), which, in theory, is meant to make music more easily transposable to other keys.
