This year, I've attended
* UX Camp Copenhagen http://uxcampcph.org
* UX Camp Europe in Berlin http://www.uxcampeurope.org
* UA Europe (European equivalent of the Writers UA conferences in the US) http://www.uaconference.eu
* TCUK (Technical Communication UK) http://technicalcommunicationuk.com
* Write The Docs Prague
* soap! in Krakow http://soapconf.com
They are all different - which is good for me especially, I think. UX Camp Europe is the biggest with about 400 people. soap! was the smallest with 170 on the first (free) day and 80 on the second ($) day. My last STC conference was in 2013. There were 800 people there. I've decided that I really prefer the smaller conferences where you really get into long, fruitful discussions with people and build not just a network, but friendships.
I'm almost alone as a tech writer at the UX camps. There, I've done Ignite!-style talks on accessibility, a preso on techcomms working with UX'ers, and a panel on women in tech. UA Conference and TCUK are more traditional techcomm conferences, but the size (150-200) means you get a lot out of it. I know the UK audience is a mix of writers for hardware, science, software, and APIs.
I also like attending local events in Copenhagen where I live. Like being a geek locavore, perhaps. I find them through Wikipedia (I'm a Wikipedian) and the WordPress community. Meetup is also a good place to find this sort of thing. Hackathons are also great places to go as a techcomms person. I attended a Charity Hack in 2010 in London where we had 24 hours to come up with an app based on eBay/PayPal's payment API (for giving to charity). That was a real learning experience where one of our developers went home without a word suddenly and never came back! Locally, cultural institutions run hackathons for hacking into all the open datasets from the museums, national archives, national broadcasting company, and others of that ilk. I missed it (HACK4DK) this year, but that is a really cool and is usually kicked off with a bunch of talks about open data. With these events, you truly do get to spend a night at the museum!