Working as a developer, tech lead or an architect, one thing that you should continue pursue is learning. Either it could be new technologies & framework or any new disruptive ideas or tools.
Some of the key developer conferences that you need to block your calendar are:
- Apple WWDC
- Google I/O
- Facebook Developer conference
- Open source summit.
If you are not able to attend one, you can still watch those couple of weeks later as part of their youtube channel.
I stumbled upon this blog which has the list of all the dev conference that happens throughout the world.