<p>I'm struggling to find the name of a connector I just broke, so I can order a new one.</p>
<p>It's a six pin nylon terminal, that plugs into a set of header pins on a stepper motor.</p>
<p>What do I search for to find these?! Also, how would I go about finding something like this in the future? I seem to struggle to find connectors.</p>
<p><a href="https://i.stack.imgur.com/ejbJR.jpg" rel="nofollow noreferrer" title="Connector"><img src="https://i.stack.imgur.com/ejbJR.jpg" alt="Connector" title="Connector" /></a></p>

In an attempt to salvage my (sadly) previously incorrect answer (at the bottom),
and
to add to
anttix's superlative answer
, here is a quote from
Stepper cable for MKS Boards pinout
, which clearly shows the difference - locking and non-locking, and pitch difference (note the thickness of the plastic between each individual pin socket) - in the two plugs:
This pinout information will help you to use our 1 meter stepper
cables correctly. Cable was made to be compatible with 6-pin JST
connectors on NEMA 17 stepper on one side and 4-pin JST connector on
other side. These cables are compatible with MKS BASE and MKS Gen
boards that we sell in our store.
For compatibility with Anet board you will need to swap 2 wires - RED
and BLUE on the 4 pin board side connector.
Whilst they aren't labeled
PH
and
XH
, it is pretty safe to assume that:
For the control board, the
4 pin
female connector
on the
left
is the
XH
, and;
For the stepper motor, the
6 pin
female connector
on the
right
is
PH
.
The
mattmillan.com
link in anttix's answer, whilst informative, unfortunately doesn't show both sides of the 4 or 6 pin connector.
For the sake of completeness, but at the risk of going
off-topic
, the connector to the printer controller board is often a DuPont, and not a JST,
particularly in
, but not limited to, Arduino (Atmel/AVR based) boards.
From the same website, this page
Stepper cable for RAMPS pinout
, shows the DuPont connector to the control board and the JST-PH-6P connector to the stepper motor (I've not fixed the typos in the quoted text):
This pinout information will help you to use our 1 meter stepper
cables correctly. Cable was made to be compatible with 6-pin JST
connectors on NEMA 17 stepper on one side and RAMPS board connector
(also called dupont connector) on other side. Main feature of RAMPS
stepper header and this cable is that you can reverse stepper
direction by turning connector on RAMPS 180 degree.
This cable is aslo compatible with CNC V3 shields for Arduino UNO and
other electronic boards for 3D Printers and CNC control. Please
observe the following piut diagram to make sure that your particular
electronic board is compatible.
Note
: I'm not promoting this particular website, it just so happens that they have the best comparison photos.
Maybe
It is most likely
not
... JST XH 2.54 6 pin female
and the reverse side, showing the locking, with the male PCB connector