Somewhat building on one that is currently mentioned on the page. Advocates have secured thousands of corporate pledges for cage-free eggs globally since 2015. That’s built global pressure for legislation, e.g. the European Commission, UK governments, and various US states have cited corporate progress as a major motivator for them to act. (I think as of latest figures about ~100M (?) US hens were cage-free vs. about 20M in 2015, when the campaigns started ramping up.) In the US, the cage-free flock size has dramatically increased in size these past few years. See, e.g., p.4. 

EAF helped pass a ballot which doubled Zurich's development aid

https://forum.effectivealtruism.org/posts/dTdSnbBB2g65b2Fb9/eaf-s-ballot-initiative-doubled-zurich-s-development-aid

Much of the concrete life saving and life improvement that GiveWell top charities have done with GiveWell-influenced donations.

80,000 Hours as a (very thorough) resource for individuals trying to do good/maximize their impact with their careers feels like a big accomplishment. I found EA when I googled "Highest impact careers/how to have the biggest impact with your career", and didn't find anything anywhere near as compelling as 80,000 Hours. I think their counterfactual impact is probably quite massive given how insufficient impact-oriented career advice is outside of 80K (and the broader communities/research/thinking/work that have led to 80K being what it is). 

Most of the impact is indirect so I'm not sure how much this answers the original question. But 80K's impact from community building (e.g. being  the most common entry point into EA nowadays, the podcast, etc.), career plan changes, and maybe most importantly, being the best resource for impact-prioritizing people looking for career advice (and especially students), feel very noteworthy. 

Giving what we can now has over 6,000 people (the accomplishments page says 5,000)

Apologies for a quick answer, rather than a thorough answer where I looked up all the links and details, but one potential source:

I believe Charity Entrepreneurship partly see one of their key outputs as being creating tangible achievements of the EA community. I guess a lot of it is still pretty new, but to the extent you can find any impressive achievements from CE-incubated orgs, those are pretty clearly attributable to EA. Fish Welfare Initiative have some impressive commitments from producers in India I think, and my impression was that some of the global health charities have achieved quite a lot in a small space of time.