The pulley wheels are the fastest spinning bearings on your bike. An upgrade to ceramic bearing therefore is the most effective upgrade. C-Bear ceramic pulley can be used both for road, cyclocross and MTB.

Full Ceramic Pulley Shimano Sram|Bi-cycle bottom bracket with ceramic bearings|c-bear.com Pulley Full Ceramic

Shimano-Sram 10/11sp
Sram  AXS 12 speed - road
Campagnolo  11 speed 
Campagnolo  12 speed 
For Road/Race use Only.
Pulley - Titanium |Bi-cycle bottom bracket with ceramic bearings|c-bear.com Pulley - Titanium

Shimano-Sram 10/11 speed
Campagnolo 11 speed

With full ceramic bearings, click here
Pulley Campagnolo|Bi-cycle bottom bracket with ceramic bearings|c-bear.com Pulley Campagnolo

11 speed  (picture here)
12 speed
13 speed Ekar
Please select options available from drop down list below.
Available in both full and hybrid ceramic bearings
Pulley Shimano-Sram|Bi-cycle bottom bracket with ceramic bearings|c-bear.com Pulley Shimano-Sram

10/11 Speed:

Aluminium
Carbon
Delrin

With full ceramic bearings, click here
And C-bear OCM (original cage max) click here
Pulley - XX1 Sram|bi-cycle ceramic bearing|c-bear.com Pulley - XX1 Sram

Sram 11 Speed
XX1
XO1
Force CX1
Force 1
Rival 1
Apex 1

 
Pulley - Sram Eagle 12 Speed|bi-cycle ceramic bearing|c-bear.com Pulley - Sram Eagle 12 Speed

XX1 Eagle
XO1 Eagle
GX Eagle
NX Eagle
SX Eagle
 
Pulley wheels OCM (Original Cage Max)|bi-cycle ceramic bearing|c-bear.com Pulley OCM (Original Cage Max)

Shimano:
Dura Ace R9200 (12speed)
Ultegra R8100 (12speed)
Dura Ace R9100, R9150 Di2
Ultegra R8000, R8050 Di2
GRX
105 R7000

SRAM AXS Road 12 speed :
Force
Red

SRAM red Etap 11 speed

SRAM AXS MTB 12 speed :
https://www.c-bear.com/en/products/pulley-sram-eagle-12-speed