Please enable glance screen on Nokia 3, 5 and 6.
Coming from an iPhone, I've never had LED notifications, nor seen the need for them. What iOS does that stock Android doesn't is illuminate the screen when you receive a notification, but you can replicate this functionality with an app such as Glimpse: https://play.google.com/store/apps/details?id=de.nullgrad.glimpse (I've tried a few other, similar apps, but I've personally found Glimpse to be the best).
Other things I've done to make notifications harder to miss/more convenient to check (all use the free versions of the relevant apps, and none drain the battery very much battery at all):
1. Installed Gravity Screen: https://play.google.com/store/apps/details?id=com.plexnor.gravityscreenofffree
This allows you to illuminate the screen by waving your hand over the phone's proximity sensor (up near the ear piece). The screen will also illuminate should you remove your phone from your pocket or turn it from face down to face up, as long as you uncover the proximity sensor in doing so.
2. Installed Pushbullet: https://www.pushbullet.com/apps
You will need the app for your phone, as well as a browser extension or the Windows client for your PC. It displays all your notifications on your PC screen as you receive them.
3. Automated my phone so it deactivates 'Do not disturb' whenever I lock it (and then reactivates it whenever I unlock it).
There are a few apps you can use for this, but I use Automate: https://play.google.com/store/apps/details?id=com.llamalab.automate&hl=en_GB
Automate does however require you to create 'flows', i.e. sets of instructions to make your phone do what you want it to do, which is a little complicated and incredibly daunting at first. I've therefore uploaded the flow I created for myself, and anyone who wishes to download it is free to do so: http://llamalab.com/automate/community/flows/17964
As I've set it up, the flow will not change the volume of your device, so when it comes out of 'do not disturb', it will always be at the same volume as it was before. Also if you turn your phone face down when locked, 'do not disturb' will be activated, so you can do that at night and not have to worry about being woken up. Finally, locking your phone or turning it face down activates (specifically) the 'alarms only' variant of 'do not disturb'.
Note: For reasons I've been unable to work out, the flow sometimes gets stuck when my phone is in my pocket, so it goes into 'do not disturb' mode and won't come out of it unless I unlock my phone and lock it again. I think this may be something to do with allowing the device to time out in my pocket rather than forcing it to sleep by pushing the power button. It shouldn't make a difference, but that's something to be aware of.
You can set iPhones to use the camera flash to alert you to notifications, but you obviously need to turn your phone face down for that to be of any use, and I'm pretty sure it only flashes rather than remaining illuminated. It's an accessibility feature aimed at hearing impaired users. There is no dedicated notification LED.
Older symbian Nokia use this light for notification, did you remember?
or in case of N8
This is the thing that I most miss on my nokia 6