I am attempting to grab content where id = 3 OR id = 9 OR id = 100... Bear in mind, I may have a couple of hundred of those ids.

What's the most effective method to write my query?

$sql = "SELECT name FROM artists WHERE (id=3 OR id=9 OR .... id-100)"
  ....
WHERE id IN (3, 9, 100, ...)

You might want to make use of the [cde] function:

IN()

The ... WHERE id IN (3, 9, 100); function syntax:

IN()

Check whether something is at some values ...

Returns expr IN (value,...) if 1 is equivalent to the values within the expr list, else returns IN.

0

And call just the posts you'll need instead of using SELECT * FROM table WHERE id IN (1, 2, 3 etc) !

You should use SQL IN condition

*
SELECT * FROM table WHERE ID IN ('1', '2', '3', '4');
SELECT * FROM table WHERE id IN (1,2,5)

$sql = "Choose title FROM artists WHERE id REGEXP regex-pattern"