Can I tell whether a LED driver/bulbs are dimmable without damaging them?
For AC powered screw-in LEDs, making them dimmable is hard.  So nobody makes an AC dimmable LED by accident and forgets to list it as dimmable.  Forget that.  

DC is a whole different kettle of fish

All the rules are different with DC.  Not least the cabling/wiring rules for circuits under 55 watts.  

However, the way dimming works is also totally different.  There is no need to deal with the balky AC waveform, nor any legacy need to play well with a 1960s-tech dimming scheme intended for incandescents.  

DC dimming is typically done with PWM, meaning the power supply is switched on and off, faster than the eye can see. 

Control is done via this same exact PWM.  A dimmer/controller's output can either control a small amount of lighting, or be the pilot signal to an amplifier that controls a great deal more lighting, or a combination of both.  

The market is awash with cheap Cheese junk, but functionally compatible products are also made and UL-listed by reputable makers. 

Also, LED is available in full color RGB and RGBW, the same basic scheme except with 3-4 channels for red, green, blue and optionally white.