Common materials for full sets of keycaps currently sold separately:

PBT, ABS, PC

Comparison of material characteristics:

Fineness: PC>ABS>PBT
Durability: PBT>>ABS>PC
Light transmittance: PC>ABS>>PBT
Color brightness: ABS>>PBT

keycap materials and processes used:

PBT keycaps are mostly made using processes such as thermal sublimation or two-color injection molding
ABS keycaps are mostly made using processes such as two-color molding or three-color molding
PC keycaps are mostly made using processes such as pad printing and UV printing

PBT keycaps

The characteristics of PBT are high temperature resistance (suitable for thermal sublimation process), wear resistance and durability (less prone to oiling than ABS keycaps);
The material feels rough and frosted, the color is darker, and the light transmittance is poor
Common processes: thermal sublimation, two-color injection molding, etc.
The thermal sublimation process can transfer complex and colorful patterns to PBT. The blank keycaps without transferred patterns are what everyone calls materials. (Due to different processes for two-color injection molding, there is no such thing as materials).
The height, thickness, shape, touch, etc. of the materials produced by different injection molding factories may be different.
In fact, it is not entirely correct to judge the material from the height alone. Even if the keycaps are of the same original height, the materials will be different as long as the molds used in production are different.
Due to the characteristics of materials and process technology, PBT keycaps processed by thermal sublimation technology have a more stable color, are easy to gray, and are more difficult to produce high-purity colors (this is also an important reason why it is difficult for PBT keycaps to achieve pure black), and direct use of the color of the design drawing for printing often has obvious color differences. It is difficult to adjust the color of thermal sublimation keycaps, so proofing and color adjustment is also a necessary process for the production of thermal sublimation PBT keycaps. This step tests the designer's experience.
The material may deform during the thermal sublimation high-temperature processing process, which is why some PBT keycaps have a certain degree of bending deformation on the four sides.
The material of PBT keycaps is usually not pure PBT, but also contains additives such as color powder and shading powder. Different proportions of additives will cause different characteristics of the material to a certain extent, such as different hardness, smoothness, and light transmittance, and it may also make PBT keycaps easier to oil.

ABS keycaps

ABS is characterized by delicate touch, but easy to wear and oil after long-term use; easy to color, accurate color, can achieve high-purity color that PBT cannot; good light transmittance, presenting a misty transparency (suitable for playing with keyboard lights, the misty effect is not too glaring).
The raw materials and processing costs of ABS keycaps are relatively low, but customized AVS keycaps are more expensive because each keycap needs to be molded independently.
Although ABS material itself is not as wear-resistant as PBT, it can improve durability to a certain extent by spraying wear-resistant materials or other special treatments.

PC keycaps

The characteristics of PC are high light transmittance, which can present a crystal clear and transparent feeling (suitable for playing with keyboard lights, but using spring transparent keycaps may make the light glare slightly when looking directly at the keyboard); the surface is easy to get fingerprints and scratches, and it is easy to turn yellow when exposed to the air for a long time; it feels sticky and astringent