Why are you using DuckDuckGo? (Instead of Google?)
PrevNode LinkNextTo prevent Filter bubble.
I like their keyboard navigation (left/right/up/down keys).
Their search URLs have less junk than Google's.
I like the bang commands ("!g" for a Google search; "!gh" for a GitHub search; "!mdn" for mdn; etc.).
Also note that DuckDuckGo claims to avoid tracking the users, but I personally do not care too much about that.