A bulb holder is a device that holds a bulb. The bulb holder types are where the bulb fits. The image below shows a bulb holder from a ceiling light.

Edison screw bulb holder types:
E10 Miniature (Flashlight lamp)
E11 Mini-Candelabra.
E12 Candelabra.
E14 European.
E17 Intermediate.
E26 Medium.
E27 Medium.

Lightbulbsocket.com, lamp sockets or lamp holders provide electrical connections to the lamps and support it in the lighting fixture. The use of sockets allows lamps to be safely and conveniently replaced (re-lamping).

Lamp holder and bulb holder types:

B Bayonet Collar Base
E Edison Screw Light Base
F Single Pin Type Base
G Multiple Pin Type Light Bulb Base
K Cable Connections
P Pre-focused Light Base
R Recessed Contact(s) Base
S Shell-type Light Bulb socket
T Telephone Slide Base
W Wedge Base
X Special Type Lightbulb socket.

There are many types of bulb holders available, but the most common ones include:

Edison screw (ES) – used for incandescent and many types of modern light bulbs
Bayonet cap (BC) – used for incandescent and many types of modern light bulbs
GU10 – used for LED spotlights
MR16 – used for low-voltage halogen spotlights
G9 – used for halogen capsule bulbs
E14 – used for small Edison screw bulbs, commonly found in chandeliers and decorative lighting fixtures
E27 – used for standard Edison screw bulbs, commonly found in lamps and ceiling fixtures
T8 – used for fluorescent tube bulbs
These are just a few examples, and there are many other types of bulb holders available for various types of light bulbs.