CZ Custom
http://czcustom.com/ and Cajun Gun Works
https://cajungunworks.com/ have all kinds of upgrade parts and services available. It all comes down to what you want to use your gun for and what you want to change about your stock gun.
I converted my P-01 Compact over to single action only so that it is like my other two CZ guns. Here's a list of the parts I bought from CGW to do it:
5SAO Single Action Only Aluminum Trigger (your preference)
TR-PIN Floating Trigger Pin
20C Hammer Spring Strut Compact (so you don't have to drive out the pins for the disco and old hammer)
RHK Race Hammer Kit (your preference)
HPIN Hammer Pin
SRS-1 Short Reset System
It is recommended that you also get a starter punch or spring-loaded center punch. Hammer pins and trigger pin can be hard to move.
There's all kinds of sight options too- night sights and fiberoptics. It depends on what you want to use the gun for and your personal preferences.
It might be best if you shot the gun some while figuring out what you want to use the gun for and what you'd like to change about it. There's lots of helpful threads and friendly knowledgeable people on this forum.