How to choose the right keycap material?

Keycap materials are mainly ABS and PBT:

ABS keycaps: lightweight and smooth, but easy to play oil.

PBT keycaps: hard and wear-resistant, not easy to play oil.

According to personal preference, if the pursuit of durability, PBT is better.

Is this keycap compatible with other brands of keyboards?

As long as your keyboard uses MX axis mechanical switches, this keycap is basically compatible.

Does this set come with a keycap puller?

Yes, it is included in the product.

Are these regular size keycaps or low profile?

These are regular size keycaps, specifically cherry profile keycaps.