It's really important to start timing your solves if you want to improve your speeds. Even though StackMat timer is the official choice, you don't have to have one in order to time your solves. Here are a few pretty neat online timers that you can use on your computer or phone.
csTimer (Source)
- Can be used offline and installed as a PWA
- Ability to use WCA Inspection
- Very customizable UI and options
- Scramble image
- Cloud sync with Google, WCA or csTimer account
qqTimer (Source)
- Minimalistic UI
- Can be used offline
- Inspection support
- Import functionality
The original version of this timer was made by Michael Gottlieb and is available here (GitHub).
Twisty Timer (Source) (Android)
- Nice UI with a range of themes and customizations
- Supports import/export
- Includes OLL and PLL trainer and algorithms reference in-app
- Supports inspection
- Ability to enable Hints for Cross/Extended Cross on 3x3
- Scramble image
ChaoTimer (iOS)
- Supports a range of gestures
Timiks (Source)
- OLL/PLL trainer
- Customizable UI
- Cloud sync with Google
timer.cubing.net (Source)
- Minimal design
- Works offline on mobile as a PWA
- Sync functionality
cTimer
- Dark mode
- Supports inspection
- Scramble image
cTimer is made by Conrad Rider, maker of VisualCube and other cubing software.
Ruwix Timer
- Customizable theme and design
- Scramble image + graph
- Supports inspection
There are tons of timers out there but I think these options are pretty great for any use case that you might have. Enjoy!