Recently, we've done a few stories on EU concepts that were relegated to Legends status, but had varying journeys since. Thrawn, of course, sets the standard for how to make the jump from EU to New Canon. Starkiller reportedly nearly "Thrawned," Rex unofficially "Thrawned" but was then "de-Thrawned," and Force Trees, Kyber Crystals, and Gray Jedi are hovering in the subtle nether regions of the New Canon, looking for potential major Thrawnage with The Last Jedi.
Several of characters, places, organizations, and technology that were re-introduced into the new canon, albeit sometimes in a form different from what we might have known from the EU.
io9 has made a listing of many of these items. As you can see, many of the items listed were "Thrawned" in Rebels, as well as Tarkin, but new canon sources are varied across the bunch.
As we noted when we reported on the fan-made New Canon timeline, there is next to nothing that precedes The Phantom Menace, with only a children's story about a younger Maz Kanata going back in time in any significant way. However, for fans of the Old Republic timeframe in (EU) history, the planet Taris has been re-canonized in the 2015 novel Star Wars: Aftermath. Additionally, the Selkath species, which is not listed by io9, was prevalent in the Knights of the Old Republic storyline, and has since been re-canonized in The Clone Wars.
EU fans of particular characters, places, and events can look forward to the possibility of their favorites being promoted back into the wonderful world of canon.